Marksparks .arkansas

CBSE Class 8 Very Short Answer Type Questions

Question 1. What is the name of the process by which young ones are formed?
Answer: Reproduction is the biological process of the formation of young ones of their kind by living organisms.

Question 2. Name two main types of reproduction prevalent in animals.
Answer: Two main types of reproduction prevalent in animals are asexual and sexual reproduction.

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Question 3. A type of reproduction involves gametes. Name it.
Answer: Sexual reproduction is the type of reproduction that involves gametes.

Question 4. The male and female gametes in human beings are known by what names?
Answer: In human beings, the male gamete is known as sperm and the female gamete as egg or ova.

Question 5. Sperms need to have mobility. ‘ Give a reason.
Answer: Sperms have to enter the female reproductive passage and fertilise the ovum by travelling through the vagina and uterus to reach the Fallopian lube. This is the reason why sperms need to have mobility.

Question 6. Only male gametes have a tail. Can you think of a reason for this?
Answer: Male gametes or sperms have a tail to facilitate the movement of sperms, which helps them to reach the egg (female gamete) for fertilisation.

Question 7. In humans, which organ produces the sperm?
Answer: Testes produce sperm in humans.

Question 8. X is the reproductive cell produced in a woman’s while Y Z Is the reproductive cell that is produced in the testes of a man. What can X, Y, and Z be?
Answer: An egg is the reproductive cell produced in a woman’s ovary, while sperm is the reproductive cell that is produced in the testes of a man.

Question 9. State whether human beings reproduce by sexual methods or asexual methods.
Answer: Human beings reproduce by the sexual method.

Question 10. Give the other name of oviducts
Answer: Fallopian tube is another name for oviducts

CBSE Class 8 Science Chapter 8 Force And Pressure Fill In The Blanks

Question 1. To draw water from a well, we have to use the _____________ rope.
Answer: Pull

Question 2. A charged body _____________ an uncharged body.
Answer: Attracts

Question 3. To move a loaded trolley, we have to do it.
Answer: Push

Question 4. The north pole of a magnet _____________ the north pole of another magnet.
Answer: Repels

Read And Learn More CBSE Class 8 Science Question And Answers

Question 5. An archer stretches her bow while aiming at the target. She then releases the arrow, which begins to move towards the target. Based on this information, fill up the gaps in the following statements using the following terms: muscular, contact, non-contact, gravity, friction, shape, attraction

Question 6. To stretch the bow, the archer applies a force that causes a change in its ___________.
Answer: shape

Question 7. The force applied by the archer to stretch the bow is an example of a ___________ force.
Answer: muscular

Question 8. The type of force responsible for a change in the state of motion of the arrow is an example of a ___________ force.
Answer: Contact

Question 9. While the arrow moves towards its target, the forces acting on it are due to ___________ and that due to the ___________ of air.
Answer: Gravity, friction.

Question 10. The ____________ the area, the larger the pressure on a surface.
Answer: Smaller

Question 11. A cyclist exerts a force of ____________ on the pedal of the cycle.
Answer: Push

Question 12. When two forces act in the same direction, then the net force acting is ____________ of the two forces.
Answer: Sum

Question 13. The force that acts when two objects are in actual contact is called _the ___________ force.
Answer: Contact

Question 14. Halting of the moving ball on its own is an example of ____________ force.
Answer: Frictional

Question 15. As we go high on the mountain, the ____________ decreases.
Answer: Pressure

Question 16. If the force is applied on a smaller area of contact, then the pressure exerted by it ____________.
Answer: Increases

Question 17. Draper and rubber sucker work on the principle of ____________ pressure.
Answer: Atmospheric

Question 18._________ is an example of contact force.
Answer: Frictional Force

Question 19. When you kick a ball with your leg, you exert _______ force.
Answer: Muscular

Question 20. _______ is the device used to measure atmospheric Pressure.
Answer: Barometer

Class 8 Science Chapter 8 Force And Pressure True Or False

Question 1. If two forces act in opposite directions, then the net force is the difference between the two forces.
Answer: True

Question 2. In ‘tug of war’, when both teams apply equal pulling force, then the net force is maximum.
Answer: False

Question 3. The force between two electric charges is called the magnetic force.
Answer: False

Question 4. Muscular force and frictional force are examples of non-contact forces.
Answer: False

Question 5. The force per unit area is the pressure on that area.
Answer: True

Question 6. The nails penetrated the planks easily because a large force acts on a small area.
Answer: True

Question 7. Water comes out more slowly from an upstairs tap than from a similar downstairs tap.
Answer: True

Question 8. The blood pressure in our body balances the atmospheric pressure acting on our body.
Answer: True

Question 9. The SI unit of pressure is the newton.
Answer: False

Question 10. Pressure is defined as the force per unit length.
Answer: False

Question 11. A liquid exerts pressure in all directions.
Answer: True

Class 8 Science Chapter 8 Force And Pressure Match The Columns

Question 1. Match Column 1 with Column 2.

Answer: (a)-(4), (b)-(3), (c)-(1), (d)-(2), (e)-(6), (f)-(5)

Class 8 Science Chapter 8 Force And Pressure

The following questions consist of two statements: Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A.
3. A is true, but R is false.
4. A is false, but R is true.

Question 1.

Assertion (A) A Push or pull on an object is called a force.
Reason (R) Forces add together if they are applied in opposite directions.

Answer: 3. A is true, but R is false because forces applied in the same direction add together.

Question 2.

Assertion (A) In the game of tug of war, sometimes the rope does not seem to move to any side even if strong forces are applied from both sides.
Reason (R): Equal forces applied from opposite sides on an object make the net applied force zero.

Answer: 1. Both statements are correct. If the net force on a body is zero, then it does not move. Hence, the correct option is (a).

Question 3.

Assertion (A): Electrostatic force is a contact force.
Reason (R) The force exerted by a charged body on another charged body is known as the electrostatic force.

Answer: 4. A is false because electrostatic force is a non-contact force. Hence, option (d) is correct.

Question 4.

Assertion (A) The larger the area, the smaller the pressure.
Reason (R) The force acting on a unit area of a surface is called pressure.

Answer: 1. According to the definition of pressure,

⇒ \(\text { Pressure }=\frac{\text { Force }}{\text { Area }} \Rightarrow \text { Pressure } \propto \frac{1}{\text { Area }}\)

Both statements are correct. Hence, option (a) is correct

Class 8 Science Chapter 8 Force And Pressure Assertion-Reason Questions And Answers

The following questions consist of two statementsAssertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below.

1. Both A and R are true, and R is the correct explanation of A.
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false.
4. A is false, but R is true.

Question 10.

1. Assertion (A) Fruit falls on the ground when it gets detached from the tree.
2. Reason (R) The force responsible for this action is the electrostatic force.

Answer: 3. A is true, but R is false.

Question 11.

1. Assertion (A) A football rolling along the ground gradually slows down and finally comes to rest.
2. Reason (R) This happens due to the force of friction between the ball and the ground.

Answer: 1. Both A and R are true, and R is the correct explanation of A.

CBSE Class 8 Science Chapter 1 Crop Management Multiple Choice Questions

Question 1. Which of the following sorts?

1. Rice, wheat, cotton
2. Mize, soybeans, mustard
3. Rice, mustard, cotton
4. Rice, maize, soybeans

Answer: Rice, wheat, cotton

Question 2. The monsoon in our country during the months

1. A pill in December
2. June September
3. November March
4. January may

Answer: June, September

Read And Learn More CBSE Class 8 Science Multiple Choice Questions

Question 3. The pictures below display two techniques.

What are the advantages of choosing a sprinkler system over a pulley system for irrigation?

1. Sprinkler system reduces the wastage of water
2. Sprinkler system decreases the water requirement of the crops
3. Sprinkler system increases the water absorption capacity of the crops
4. A sprinkler system provides excess water to the crops for high productivity

Answer: A Sprinkler system reduces the wastage of water

Question 3. Which one of the following conditions is not essential for growing maize?

1. High Temperature
2. Humidity
3. low temperature
4. Rainfall

Answer: Low temperature

Question 4. The process of loosening and turning of Soli is called

1. Litigation mid-managing,
2. Digging mid-winnowing
3. Tilling mid-ploughing
4. Harvesting mid-storage

Answer: Tilling mid-ploughing

Question 5. Which of the following tools would a farmer use to remove weeds from the field?

1. Hoe
2. Plough
3. Axe
4. Cultivator

Answer: Hoe

Question 6. The planting of seeds in the soil is called

1. Cultivation
2. Irrlgation
3. Harvesting
4. Sowing

Answer: Sowing

Question 7. A seed drill is used to

1. Snow the seeds
2. Remove the weeds
3. Remove the pest
4. Mix manure into the soil

Answer: Snow the seeds

Question 8. A former aim was to enhance the soil nutrients in Ills field without using chemical fertilisers. What natural method should he consider for replenishing the soil?

1. Sowing healthy seeds
2. Growing the same crops every year
3. Growing different crops alternatively
4. Supplying water to crops at regular intervals

Answer: Growing different crops alternatively

Question 9. Which of the following syntomonts is not true for organic manure?

1. It enhances water water-holding capacity of the soil
2. It has a balance of all plant nutrients
3. It provides humus to soli
4. It improves the texture ofsoil

Answer: It has a balance of all plant nutrients

Question 10. Which of the following is not true for fortelisers?

1. They increase the yield
2. Their exterior use disturbs the balance of nutrients in till’ Nllll
3. They provide a lot of humus for the soil
4. They need not be environment-friendly

Answer: They provide a lot of humus to the soil

Question 11. Read the statement given below.

1. Seeds require moisture for germination.
2. Plants can absorb nutrients mostly in dissolved form.
3. Irrigation protects crops from both frost and hot air currents.
4. Irrigation improves soil texture

Answer: Irrigation protects crops from both frost and hot air currents.

Choose the combination of statements that includes the need to irrigate crops.

1. (1) and (2)
2. (1) and (3)
3. (1), (2), and (4)
4. (1) and (3)

Question 12. Waiting for the crops at regular Intervals Is called

1. Sowing
2. Manuring
3. Tilling
4. Irrigation

Answer: Irrigation.

Question 13. Consider the following list of food Items

1. Honey
2. Wheat
3. Sunflower oil
4. Eggs
5. Fish oil
6. Beans
7. Pulses
8. Cheese
9. Milk
10. Apple

Which choice categorizes sources of the food Items correctly?

Answer: 4. Eggs

CBSE Chapter 1 Crop Management Long Answer Questions

Question 1. Soham investigates the water holding capacity of four different types of soils. He sets up an experiment for each type of soil as shown in the diagram. Soham records his observation in a table.

Question 2. Which type of soil absorbs the most water?

1. Clay
2. Loam
3. Sand
4. Silt

Answer: Clay

Soham added the same amount of water to each type of soil. State one more thing that Soham needs to keep the same in his experiment.

Answer: The amount of each soil type on the filter paper must remain the same for the experimental setup

Read And Learn More CBSE Class 8 Science Long Answer Questions

Question 2. Paddy is a major cereal crop in our country.

1. In which season is paddy cultivated?
2. Discuss the method of sowing.
3. What measures must be taken to prevent the spoilage and insect attack of harvested grains?

Answer:

1. Paddy is cultivated in the rainy season as it is a Kharif crop
2. For sowing paddy, seeds are first grown in a nursery, and later, seedlings are transplanted. In the field. This allows us to select only healthy and better seedlings for cultivation
3. Measures taken to prevent the spoilage or damage of harvested crops from insect attack are
   1. Exposing them to sunlight for drying, as freshly harvested crops have moisture.
   2. Dried neem leaves are kept with stored grains to prevent damage from pests.
   3. Specific chemical treatments are also available for preventing crops from spoilage and insect attacks

Question 3. Explain various agricultural practices in a sequential manner
Answer: Various agricultural practices are as follows

Preparation of soil. The first step is the preparation of the soil. In this, the soil is loosened and turned up. It helps the plants to grow and develop. The process of loosening and turning the soil is called tilling or ploughing. Sometimes manure is also added to the soil before tilling.

Sowing After preparation of the soil, the second step, called sowing, takes place. It is the process of scattering or planting seeds into the soil before sowing good Good-quality seeds are selected. The seeds should be clean and healthy.

Adding manure and fertiliser soil supplies minerals and nutrients to the crops. These nutrients are essential for the growth of plants. Sometimes these nutrients are lacking, so substances are added to maintain or replenish the soil. These substances are called manure and fertilisers. Manures and fertilisers are essential to increase crop production

Irrigation: The process of watering the crop plants at regular intervals is called Irrigation. Plants take all the nutrients and minerals in dissolved form. So, water is most essential for the germination of seeds, growth, and development of plants.

Harvesting After maturation, the crop is cut off. This process is called harvesting. It is done by a sickle or by a machine called a harvester.

Storage of the product is one of the most important tasks. To keep the grains for longer, they should be safe from moisture, pests, insects, and other microorganisms.

Question 4. As a part of the eco-club activity, students were asked to raise a kitchen garden on the school premises. They were provided with some materials given in the box. List the other materials you would require. How will you plan the garden? Write the steps.

Khurr: water-can, spade, shovel

Answer:

Besides the given tools, the other items required for raising a garden are seeds and seedlings of vegetables, plants from a nursery, kitchen waste, manure, water, soil, etc.

Steps for raising the garden.

1. Kitchen waste will be collected and composted in a pit.
2. A patch of land will be identified for the garden.
3. Soil will be dug up and levelled with the help of a spade.
4. Sowing of seeds/ transplanting of seedlings will be done at an even distance.
5. Seeds/seedlings are selected as per the season. Water the plants regularly with a watering can.
6. Compost or manure will be applied.
7. Weeds will be removed periodically with the help of Kliurpi.

Question 5. You must have heard farmers talking about soil fertility. What is it? Mention some methods by which the soil fertility can be replenished.
Answer: The ability of soil to supply all the essential plant nutrients to a crop in adequate quantity is called soil Fertility. Repeated growing of crops in the same soil removes various nutrient elements from the soil, due to the soil lose its fertility.

1. The soil fertility can be replenished or regained by the following methods
2. By putting manure and fertiliser in the soil.
3. By practising crop rotation.
4. By growing leguminous plants or crops like pulses, peas, beans, groundnut, etc..

CBSE Chapter 1 Crop Management Short Answer Questions

Question 1. Classify the following crops into Kharif and Rabi crops and write in the tabular column given below. Maize, paddy, mustard, pea, gram, wheat, groundnut

Answer: From the above given crop list, the Kharif and Rabi Crops can be grouped as

Question 2. The levelling of a ploughed field is beneficial. Give reasons to support your
Answer: The levelling of a ploughed field is beneficial for the following reasons

1. It helps in the uniform distribution of water in the fields during irrigation.
2. It also prevents loss of moisture from the ploughed soil.
3. It ensures ever germination and uniform growth of crops.

Read And Learn More CBSE Class 8 Science Short Answer Questions

Question 3. Beera wants to practice crop rotation in his field. Suggest a Rabi crop and a Kharif crop that will replenish his field with nitrogen. Which crop replenishes nitrogen and why?
Answer: Rabi crops are pea and grain, while Kharif crops are soybean. These are grown in different seasons and therefore can very well be rotated alternately. Pea and soybean are leguminous plants that harbour bacteria, i.e., Rhizobium, in their root nodules.

These bacteria convert atmospheric nitrogen into a usable form for plants. These nitrogen-fixing plants can replenish nitrogen in the field, and hence, Beera can easily practice crop rotation.

Question 4. Leguminous plants do not require nitrogenous fertilisers. Why Is It so?
Answer: The planting of a leguminous crop in a field has the same effect as adding nitrogenous fertiliser in the field. They can fix atmospheric nitrogen themselves by using nitrogen-fixing bacteria in their root nodules. Therefore, nitrogenous fertilisers are not required for growing leguminous plants.

Question 5. State two advantages of using chemical fertilisers over manure. What would happen if fertilisers are used in excess?
Answer: Advantages of using chemical fertilisers over manure

Fertilisers are nutrient-specific and provide specific nutrients to the oil in the desired quantity.

These being readily soluble in water can he absorbed easily by the crop plants.

If it is used in excess, it causes tremendous changes in the chemical nature of the soil and makes it less fertile.

Question 6. Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.

Answer: Flow chart for the crop production of sugarcane

Question 8. Explaining how to go to the continuous plantation of crops in the field.
Answer: Soil supplies mineral nutrients to the crop. These mineral nutrients are essential for the growth of plants. If crops are grown continuously in the same field for a long period, lie soil becomes poorer in nutrients. Titus, the soil gets deficient in nutrients, and the field becomes infertile.

CBSE Chapter 1 Crop Management Very Short Answer Questions

Question 1. Explaining the meaning of crop.
Answer: The same kind of plants grown and cultivated on a large scale in one place are called a crop.

Question 2. During which months do farmers grow mustard in India?
Answer: Farmers grow mustard from October to March. Mustard is a table crop that is sown at the beginning of winter (October-November), as it needs low temperatures, and harvested at the end of winter (April-May)

Read And Learn More CBSE Class 8 Science Very Short Questions And Answers

Question 3. Terms minted to agricultural practices are given below. Rom range them in the correct sequence. Harvesting, sowing, manuring, tilling, and ploughing, Irrigation, weeding
Answer: The correct sequence in the series of agricultural practices is Tilling and ploughing > sowing > planting> irrigation> weeding > harvesting.

Question 4. If you are given a dry piece of land for cultivation, what will you do before sowing the seeds?
Answer: Before sowing on a dry piece of land, it can be prepared to prepare the soil for cultivation, such as soil preparation, irrigation, leveling, and seedbed preparation.

Question 5. Which activity of the farmer can promote the growth of earthworms and microbes in the field?
Answer: Ploughing of the soil during soil preparation creates aeration and loosens the soil, which promotes the growth of earthworms and microbes and releases nutrients In the soil.

Question 6. Pick out the odd one from the following words given in the box and give a reason for it. Plough, Seed drill, Hoe, Chain pump, Sickle
Answer: The Seed drill is an odd pair in the above-given set of tools. It is a modern agricultural tool used to sow seeds at uniform distances and to properly cover them with soil.

Question 7. What are organic foods?
Answer: The crops (foods) that are cultivated using organic substances like manures are known as organic food. These products are grown and processed without the use of synthetic chemicals, including fertilisers, pesticides, weedicides, etc…

Question 8. Is the time and frequency of irrigation the same for rice and cotton?
Answer: No, the time and frequency of Irrigation Are not the same for rice and cotton. Klee requires more frequent mulching and continuous flooding, while cotton requires less frequent deep watering. The specific Irrigation practices may vary depending on the climate, soil, and the mid-growth stage of the crops

CBSE Class 8 Science Chapter 1 Crop Management Activity Ideas

Activity 1

Aim: To separate good and healthy seeds of wheat from the damaged ones.

Materials Required: Seeds of wheat, a beaker, and water. Procedure

1. Take a beaker and fill half of it with water.
2. Now, put some seeds of wheat in it and stir it well.
3. Let it rest for some time.

Observation After some time, we observe that most of the seeds will settle down, while some seeds will float on the top.

Read And Learn More CBSE Class 8 Science Activities

Conclusion: From this activity, we can conclude that the seeds that settle down at the bottom of the beaker are heavy and healthy. The seeds that float on the top of the water are spoiled. These seeds may be damaged due to disease or eaten by pests, causing them to turn hollow and lightweight, allowing them to float on water

CBSE Class 8 Science Chapter 1 Crop Management Practical Activities

Activity 2

Aim: To show the effect of manure and fertiliser on the growth of a plant (using germinated gram seedlings).

Materials Required: Pots, soil, cow dung manure, urea (chemical fertiliser), water, and germinated gram seedlings. Procedure

1. Take three pots and mark them A, I, and C.
2. In pot A, add some soil mixed with cow dung manure
3. In pot 13, add soil mixed with urea (chemical fertiliser).
4. In pot C, put some soil only.
5. Pour an equal amount of water into each pot and plant the seedlings of gram (already germinated).
6. Keep the pots in sunlight and water them daily, for 7-10 days

Observation: After 7-10 days, the growth of seedlings was observed. Plant in pot 13 shows maximum growth, followed by plant in pot A. Plant in pot C shows the least growth among the three.

Conclusion: From this activity, we can conclude that in the soil mixed with fertilisers, plants exhibit maximum growth. The fertilisers are more soluble in water and readily absorbed by plants as compared to manure. It also shows that manure and fertilisers are required for better growth of plants.

CBSE Chapter 1 Crop Management Fill In The Blanks

Question 1. The same kind of plants grown and cultivated on a large scale at a place are called
Answer: Crop

Question 2. The first stop before growing crops is the soil.
Answer:  Preparation

Question 3. Damaged seeds would
Answer: Float

Question 4. For growing a crop, sufficient sunlight, water, and water from the soil are essential.
Answer: Water, Nutrients

Read And Learn More CBSE Class 8 Science Question And Answers

Question 5. Growing different crops alternately on the same land is called _________.
Answer: Crop rotation

Question 6. The main part of the plough is a long log of wood which is called a ___________.
Answer: Plough

Question 7. Tho crops grown in the rainy season are called
Answer: Kltarif crops

Question 8. Cotton cannot be grown in the……..season
Answer: Winter

Question 9. Poa belongs to the crops…..
Answer: Rabi

Question 10. Ploughing helps the roots to………deep in the soil.
Answer: Penetrate

Question 11……….It is a process to loosen the soil
Answer: Tilling

Chapter 1 Crop Management True/False

Question 1. Using good-quality seed is the only criterion to get a high yield.
Answer: False, apart from good quality seeds, using appropriate agricultural practices is also important for getting a higher yield

Question 2. All crop plants are sown as seeds in the field.
Answer: False, some crop plants need transplantation

Question 3. Growing different crops in different seasons in the same field will deplete the soil.
Answer: False, it enriches the soil

Question 4. Cells of root nodules of leguminous plants fix nitrogen.
Answer: False, Rhizobium (bacteria) present in the cells of root nodules of leguminous plants fix nitrogen

Question 5. Freshly harvested grains must be dried before storing
Answer: True

Question 8. Fertilisers are organic substances obtained from the decomposition of plant and animal wastes.
Answer: False

Question 9. Stubs burning in the fields cause air pollution.
Answer: True

Chapter 1 Crop Management Match The Columns

Question 1. Match the items in Column A with those in Column B.

Answer: (a)-(5), (b)-(4), (c)-(2), (d)-(3)

Question 2. Match Column 1 with Column 2.

Answer: 1. A-2.IM.C-l.D-3

Question 3. Match Column 1 with Column 2

Answer: 2. A-3, B-1.C-2.D-4

Question 4. Match Column 1 with Column 2.

Answer: A-2, B-5, C-l, D-3, E-4

Chapter 1 Crop Management Questions

Question 1. Boojho wants to know what tools like Khurpl, Shovol, and plough
Answer: We use tools like khurpl, s’ckle, shovel, plough, ete, in agricultural activities.

Question 2 Boojho wants to know, since we all need food, how li enn we provide food to a large number of people in our country?
Answer: Large-scale production of food is essential to meet the needs of a sizable population, ll requires regular production, proper management, and distribution of food

Question 3. One day, Pahell saw her mother put some gram seeds in a vessel and pour some water on them. After a few minutes, some seeds started to float on top. She wondered why some seeds floated on water.
Answer: Damaged seeds become hollow and thus lighter. Therefore, they float on top of water.

Question 4. Boojho saw a nursery near his school. He found that little plants were kept in small bags. He wants to know why.
Answer: Seeds of a few plants, such as paddy, are first grown in a nursery. When they grow into seedlings, they are transplanted to the field manually. Some forest plants and flowering plants are also grown in the nursery.

Question 5. Boojho went to a farm and saw a healthy crop growing there. Whereas in the neighbouring farm, the plants were weak. He asked Paheli why some plants grow better than others.
Answer: The plants with proper manuring and care grow better than others.

Question 6. Boojho asked the farmer if other plants were growing along with wheat. He wanted to know if they had been purposely grown.
Answer: No, these plants are not purposely grown. In a crop field, many other undesirable plants may grow naturally along with the crop. These undesirable plants are called weeds

Question 7. Boojho wants to know whether weedicides have any effect on the portion bundling through the weedicide sprayer?
Answer: Ym, spraying of weedicides may diet of furnicrit.

Question 8. One day, Pahell saw my mother putting some noom lonvos in nn Iron drum containing water. She wondered why.
Answer: Dried neem leaves are used for storing food grains at home. They protect the wheel from insects, pests, and fungal growth.

Chapter 1 Crop Management CBSE Board Crop Production

The following questions consist of two statements. Assertion and Reason (R). Answer the following questions by selecting the appropriate option given below

Crop Production and Management Important Questions

1. Both A and R are true, and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. A is false, but R is true

1. Assertion: Paddy is a Rabi crop.
Reason (R) It requires a lot of water and is grown in the rainy season.

Answer: A is false, but R is true. A can be corrected as Paddy is a Kharif crop. It is sown in the rainy season as it requires a lot of water to grow

2. Assertion: Farmers add manure to the fields to replenish the soil with nutrients.
Reason (R) Continuous cultivation of crops makes the soil poor in nutrients.

Answer: Both A and R are true, and R is the correct explanation of A

3. Assertion: In a drip irrigation system, water is not wasted at all.
Reason (R) In a drip irrigation system, water escapes from rotating nozzles and gets sprinkled on the crop as if it is raining.

Answer: A is true, but R is false. R can be corrected as in a drip irrigation system, where water falls drop by drop directly near the roots. It is a boon in regions where the availability of water is poor

4. Assertion: Weeds should not be removed from fields.
Reason (R) They compete with the crop plants for water, nutrients, space, and light

Answer: A is false, but R is true. Can he correct Weeds, should he be removed from the fields because they compete with the crop plants for water, nuirleni. space and light. Thus, they affect the growth of the rice crop.

The following questions consist of two statements:

Assertion and Reason (R). Answer these questions by selecting the appropriate option given below.

1. Both A and R are true, and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. A is false, but R is true

Question 1.

Assertion: Water plays an important role in crop production.
Reason (R) It protects the crop from both frost and hot air currents.

Answer: Both A and R are true, and R is the correct explanation of A

Question 2.

Assertion: Harvested grains should be protected from moisture.
Reason (R): Moisture prevents the growth of moulds.

Answer: A is true, but R is false

Common ailments like cold, influenza (flu), and most coughs are caused by viruses. Serious diseases like polio and chickenpox are also caused by viruses

CBSE Class 8 Science Chapter 2 Microorganisms: Friend And Foe Multiple Choice Questions

Question 1. The two microorganisms that live in symbiotic association in lichens are

1. Fungus And Protozoan
2. Algae And Bacteria
3. Bacteria And Protozoan
4. Algae And Fungi

Answer: 4. Algae And Fungi

Question 2. The gas released during the preparation of bread is

1. Oxygen
2. Nitrogen
3. Carbon Dioxide
4. Sulphur Dioxide

Answer: 2. Nitrogen

Read And Learn More CBSE Class 8 Science Multiple Choice Questions

Question 3. Alcohol is produced with the help of 

1. Sodium Chloride
2. Yeast
3. Nitrogen
4. Carbon Dioxide

Answer: 2. Yeast

Question 4. Scientist who discovered fermentation?

1. Alexander Fleming
2. Louis Pasteur
3. Johann Mendel
4. Charles Darwin

Answer: 2. Louis Pasteur

Question 5. Pathogenic microorganisms present in host cells are killed by medicines called

1. Pain killer
2. Antibodies
3. Antibiotics
4. Vaccines

Answer: 3. Antibiotics

Question 6. Which of the elements is mixed with the feed of livestock and poultry to check microbial Infection In animals?

1. Vaccine
2. Antibiotic
3. Yeast
4. Alcohol

Answer: 2. Yeast

Question 7. Antibiotics are not effective against

1. Cold And Flu
2. Tuberculosis
3. Cholera
4. Typhoid

Answer: 1. Cold And Flu

Question 8. Edward Jenner discovered the vaccine for

1. Smallpox
2. Chicken Pox
3. Tuberculosis
4. Diphtheria

Answer: 1. Smallpox

Question 9. Polio drops given to children are a

1. Bacteria
2. Algae
3. Vaccine
4. Medicine

Answer: 3. Vaccine

Question 10. A female Anopheles mosquito carries the parasite of

1. Dengue
2. Cholera
3. Malaria
4. Tuberculosis

Answer: 2. Cholera

Question 11. Dengue fever is transmitted by

1. Female Aedes Mosquito
2. Housefly
3. Female Anopheles Mosquito
4. Sandfly

Answer: 1. Female Aedes Mosquito

Question 12. The disease caused by a protozoan and spread by an insect is

1. Dengue
2. Malaria
3. Polio
4. Measles

Answer: 2. Malaria

Question 13. An example of a bacterial disease occurring in animals is

1. Foot And Mouth Disease
2. Bird Flu
3. Anthrax
4. Swine Flu

Answer: 3. Anthrax

Question 14. Anthrax is caused by

1. Bacillus anthracis
2. Salmonella
3. Clostridium
4. Aspergillus

Answer: 1. Bacillus anthracis

CBSE Class 8 Microorganisms Friend And Foe MCQ With Answers

Question 15. Citrus canker is a common disease of

1. Human
2. Plant
3. Animal
4. Fungi

Answer: 2. Plant

Question 16. Payal dug two pits, A and Bin her garden. In pit A, she put a polythene bag packet with some agricultural waste. In pit B, she dumped the same kind of waste, but without packingit in a polythene bag. She then covered both the pits with soil. What did she observe after a month?

1. Waste in pit A degraded faster than that in pit B
2. Waste in pit B degraded faster than that in pit A
3. Waste in both pits degraded almost equally
4. Waste in both pits did not degrade at all

Answer: 2. Waste in pit B degraded faster than that in pit A

CBSE Class 8 Science Chapter 2 Microorganisms: Friend And Foe Long Answer Questions

Question 1. A trash can contains the following materials. Plastic straw, Aluminium foil, Tissue paper, Glass bottles, Chicken bones.

1. Select the materials from the list that can be decomposed by microbes.

Answer: Tissue paper, Chicken bones.

2. Rohit is suffering from a stomach ache and is passing watery stools. What should Rohit do to prevent the spread of infection to other family members?

1. He should eat properly cooked food
2. He should wear a mask all the time
3. He should maintain a distance from other family members
4. He should wash his hands with soap after using the bathroom

Read And Learn More CBSE Class 8 Science Long Answer Questions

Answer: 4. He should wash his hands with soap after using the bathroom.

Microorganisms: Friend And Foe Class 8 LAQS with Answers

Question 2. Suman wants to see how quickly carrots lose colour. Loss of colour shows rotting of the carrot. She observes carrot slices on a plate under three different conditions, as shown below

She notes how long the carrot slices on each plate take to change colour

1. What can Suman conclude from her activity?
2. Carrots, when kept under the Sun, do not rot easily.
3. Carrots at room temperature lose colour more quickly.
4. Carrots can be best preserved in hot and moist conditions.
5. Carrots take more time to lose colour under cold conditions.

Answer:

1. Carrots take more time to lose colour under cold conditions.
2. Use the results of the activity to finish the graph below. The first bar is drawn for you. Put a label in the space provided for the axis on the left.

Answer:

Question 3. The picture shows the nitrogen cycle

1. How do plants take up nitrogen?
Answer: Plants take up nitrogen from the nitrogenous compounds in the soil.

2. Plants and animals are continuously using nitrogen. Will there be a depletion of nitrogen in the environment due to this continuous use? Explain your answer.
Answer: No, nitrogen in the environment will not get depleted because it is recycled and reused in the environment.

Question 3. Give the causative microorganism, mode of transmission, and one preventive measure of human diseases like Polio, Cholera, and Hepatitis B.
Answer: