Our Environment: Class 10 Science Q&A · Page 2

50 free answers on Our Environment (Science) for Class 10 students, across CBSE, ICSE and State boards.

Question & Answer

Questions

50 TOTAL

ScienceClass 10CBSE
1. Which group of organisms are not constituents of a food chain? (i) Grass, lion, rabbit, wolf (ii) Plankton, man, fish, grasshopper (iii) Wolf, grass, snake, tiger (iv) Frog, snake, eagle, grass, grasshopper (a) (i) and (iii) (b) (iii) and (iv) (c) (ii) and (iii) (i) and (iv)
Soln: Answer is (c) (ii) and (iii) Explanation: In option ii) plankton does not eat grass. In option iii) none of them eat grass hence option c) is the right answer.
ScienceClass 10CBSE
1. Which of the statement is incorrect? (a) All green plants and blue green algae are producers (b) Green plants get their food from organic compounds (c) Producers prepare their own food from inorganic compounds Plants convert solar energy into chemical energy
Soln: Answer is (b) Green plants get their food from organic compounds Explanation: Green plants produce their food by harnessing solar energy. Solar energy is used to prepare carbohydrate with the help of CO2 and water which are in-organic substances.
ScienceClass 10CBSE
1. Which of the following limits the number of trophic levels in a food chain? (a) Decrease in energy at higher trophic levels (b) Sufficient food supply (c) Polluted air Water
Soln: Answer is (a) Decrease in energy at higher trophic levels Explanation: Available energy level at a particular trophic level is 10 times the energy level at next tropic level. When we reach fourth trophic level; a minute portion of energy from producer is available.
ScienceClass 10CBSE
1. In the following groups of materials, which group (s) contains only non-biodegradable items? (i) Wood, paper, leather (ii) Polythene, detergent, PVC (iii) Plastic, detergent, grass (iv) Plastic, bakelite, DDT (a) (iii) (b) (iv) (c) (i) and (iii) (ii) and (iv)
Soln: Answer is (d) (ii) and (iv) Explanation: Group i) has wood and leather which are biodegradable. Group iii) has grass which is biodegradable hence the answer is d) (ii) and (iv)
ScienceClass 10CBSE
1. Excessive exposure of humans to U V-rays results in (i) damage to immune system (ii) damage to lungs (iii) skin cancer (iv) peptic ulcers (a) (i) and (ii) (b) (ii) and (iv) (c) (i) and (iii) (iii) and (iv)
Soln: Answer is (c) (i) and (iii) Explanation: UV rays affect upper surface our body. UV rays lead to skin cancer and effect on skin will affect our immune system as skin is considered as primary level of immune barrier.
ScienceClass 10CBSE
1. Flow of energy in an ecosystem is always (a) unidirectional (b) bidirectional (c) multi directional no specific direction
Soln: Answer is (a) unidirectional Explanation: Flow of energy is from prey to predator and it cannot be in reverse direction . Hence flow of enrgy is uni- directional.
ScienceClass 10CBSE
1. Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the (a) food web (b) ecological pyramid (c) ecosystem food chain
Soln: Answer is (a) Food Web
ScienceClass 10CBSE
1. In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of (a) heat energy (b) light energy (c) chemical energy mechanical energy
Soln: Answer is (c) chemical energy Explanation: Energy is available for transfer from one trophic level to the next in the form of food. Food is a chemical form of energy.
ScienceClass 10CBSE
1. Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called (a) decomposers (b) producers (c) herbivores carnivores
Soln: Answer is (b) producers Explanation: Producers use solar energy to synthesize food from water and carbon-di-oxide. Plants and few micro-organisms are the producers. Organisms that decompose organic material are called decomposers. Herbivores are the organisms that feed on plant and its products. Carnivore are the ones which feed on other organisms.
ScienceClass 10CBSE
1. Depletion of ozone is mainly due to (a) chlorofluorocarbon compounds (b) carbon monoxide (c) methane pesticides
Soln: Answer is (a) chlorofluorocarbon compounds
ScienceClass 10CBSE
1. Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as (a) eutrophication (b) pollution (c) biomagnification accumulation
Soln: Answer is (c) biomagnification Explanation: Eutrophication is richness of nutrient beyond optimum Eutrophication occurs due to run off from land. Introduction of an undesired substance into Pollution leads to harmful effects on living organisms.
ScienceClass 10CBSE
1. In the given food chain, suppose the amount of energy at fourth trophic level is 5 kJ, what will be the energy available at the producer level? Grass → Grasshopper → Frog → Snake → Hawk (a) 5 k J (b) 50 k J (c) 500 k J (d) 5000 k J
Soln: Answer is (d) 5000 k J Explanation: Available energy level at a particular trophic level is 10 times the energy level at next tropic level. Hence, energy at third level trophic level is 50kj. Second level trophic has 500 KJ energy and 1st level trophic level (Producer) has energy of 5000 KJ.
ScienceClass 10CBSE
1. An ecosystem includes (a) all living organisms (b) non-living objects (c) both living organisms and non-living objects sometimes living organisms and sometimes non-living objects
Soln: Answer is (c) both living organisms and non-living objects Explanation: An ecosystem is a complex of living and nonliving organisms and their interactions.
ScienceClass 10CBSE
1. In a food chain, the third trophic level is always occupied by (a) carnivores (b) herbivores (c) decomposers producers
Soln: Answer is (a) carnivores Explanation: First trophic level are producers, second tropic level are herbivores, third trophic level is occupied by carnivores.
ScienceClass 10CBSE
1. Which one of the following is an artificial ecosystem? (a) Pond (b) Crop field (c) Lake (d) Forest
Soln: Answer is (b) Crop field Explanation: Crop field is a man made ecosystem.
ScienceClass 10CBSE
Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?
The ozone layer is a protective cover for the earth. It prevents harmful UV rays from entering the earth as these rays are harmful and can result in skin cancer. But, air pollutants like chlorofluorocarbons (CFCs) are the main reason for the depletion of the ozone layer. Too much of UV rays are harmful to plants as they affect photosynthesis and destroy planktons and decomposers. These are the reasons why the damage to the ozone layer is a cause of concern. As
ScienceClass 10CBSE
If all the waste we generate is biodegradable, will this have no impact on the environment?
Biodegradable wastes are decomposed by the microorganisms into simpler substances which can be used by the producers as raw materials. But the following are the effects of too many biodegradable wastes: As the decomposition of biodegradable wastes is slow, they produce an awful smell, and when inhaled by humans, it can be harmful. The dumping areas can be a place where harmful organisms may start to breed, which can be harmful
ScienceClass 10CBSE
What are the problems caused by the non-biodegradable wastes that we generate?
Solution: The following are the problems caused by non-biodegradable wastes: These substances cannot be decomposed by microorganisms. As the quantity increases, dumping becomes a problem. Non-biodegradable wastes, like heavy metals, may enter the food chain at the upper trophic levels. They may escape to the groundwater, which causes soil infertilit
ScienceClass 10CBSE
What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Biological magnification can be defined as the progressive increase in the concentration of non-biodegradable wastes in the food chain. As there is an increase in the magnification at the successive trophic levels of the ecosystems, all the other levels do get affected, and the concentration may vary when compared to the first level.
ScienceClass 10CBSE
Will the impact of removing all the organisms in the trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
Yes, the impact of removing all the organisms in a trophic level will be different for different trophic levels. For example, if all the producers are removed, there is a chance of death or migration of the primary consumers, which will upset the trophic levels. This is the same for all levels. Therefore, the removal of organisms at any level would upset the whole ecosystem as the food chain is disturbed. The survival of the higher-level animals is completely dependent on the animals

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Our Environment: Class 10 Science Q&A · Page 2

Questions

1. Which group of organisms are not constituents of a food chain? (i) Grass, lion, rabbit, wolf (ii) Plankton, man, fish, grasshopper (iii) Wolf, grass, snake, tiger (iv) Frog, snake, eagle, grass, grasshopper (a) (i) and (iii) (b) (iii) and (iv) (c) (ii) and (iii) (i) and (iv)

1. Which of the statement is incorrect? (a) All green plants and blue green algae are producers (b) Green plants get their food from organic compounds (c) Producers prepare their own food from inorganic compounds Plants convert solar energy into chemical energy

1. Which of the following limits the number of trophic levels in a food chain? (a) Decrease in energy at higher trophic levels (b) Sufficient food supply (c) Polluted air Water

1. In the following groups of materials, which group (s) contains only non-biodegradable items? (i) Wood, paper, leather (ii) Polythene, detergent, PVC (iii) Plastic, detergent, grass (iv) Plastic, bakelite, DDT (a) (iii) (b) (iv) (c) (i) and (iii) (ii) and (iv)

1. Excessive exposure of humans to U V-rays results in (i) damage to immune system (ii) damage to lungs (iii) skin cancer (iv) peptic ulcers (a) (i) and (ii) (b) (ii) and (iv) (c) (i) and (iii) (iii) and (iv)

1. Flow of energy in an ecosystem is always (a) unidirectional (b) bidirectional (c) multi directional no specific direction

1. Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the (a) food web (b) ecological pyramid (c) ecosystem food chain

1. In an ecosystem, the 10% of energy available for transfer from one trophic level to the next is in the form of (a) heat energy (b) light energy (c) chemical energy mechanical energy

1. Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called (a) decomposers (b) producers (c) herbivores carnivores

1. Depletion of ozone is mainly due to (a) chlorofluorocarbon compounds (b) carbon monoxide (c) methane pesticides

1. Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as (a) eutrophication (b) pollution (c) biomagnification accumulation

1. In the given food chain, suppose the amount of energy at fourth trophic level is 5 kJ, what will be the energy available at the producer level? Grass → Grasshopper → Frog → Snake → Hawk (a) 5 k J (b) 50 k J (c) 500 k J (d) 5000 k J

1. An ecosystem includes (a) all living organisms (b) non-living objects (c) both living organisms and non-living objects sometimes living organisms and sometimes non-living objects

1. In a food chain, the third trophic level is always occupied by (a) carnivores (b) herbivores (c) decomposers producers

1. Which one of the following is an artificial ecosystem? (a) Pond (b) Crop field (c) Lake (d) Forest

Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

If all the waste we generate is biodegradable, will this have no impact on the environment?

What are the problems caused by the non-biodegradable wastes that we generate?

What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?

Will the impact of removing all the organisms in the trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?