Our Environment : NCERT Exemplar


Multiple Choice Question :

Q.1 Which one of the following is an artificial ecosystem? 

(a) Pond

(b) Crop field

(c) Lake

(d) Forest

Sol. (b) 

Q.2 In a food chain, the third trophic level is always occupied by

(a) Carnivores

(b) Herbivores

(c) Decomposers

(d) Producers

Sol. (a) 

Q.3 An ecosystem includes

(a)All living organisms

(b)Non-living objects

(c)Both living organisms and non-living objects

(d)Sometimes living organisms and sometimes non-living objects

Sol. (c) 

Q.4 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

Sol. (d) 

Q.5 Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as





Sol. (c) 

Q.6 Depletion of ozone is mainly due to

(a)Chlorofluorocarbon compounds

(b)Carbon monoxide



Sol. (a) 

Q.7 Organisms which synthesise carbohydrates from inorganic compounds using radiant energy are called

(a) Decomposers

(b) Producers

(c) Herbivores

(d) Carnivores

Sol. (b) 

Q.8 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

(d) Mechanical energy

Sol. (c) 

Q.9 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

(d) Food chain

Sol. (b) 

Q.10 Flow of energy in an ecosystem is always



(c)Multi directional

(d)No specific direction

Sol. (a) 

Q.11 Excessive exposure of humans to U V-rays results in

(a) damage to immune system

(b) damage to lungs

(c) skin cancer

(d) peptic ulcers

(i) and (ii)

(ii) and (iv)

(i) and (iii)

(iii) and (iv)

Sol. (c) 

Q.12 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



(c)(i) and (iii)

(d)(ii) and (iv)

Sol. (d) 

Q.13 Which of the following limits the number of trophic levels in a food chain?

(a) Decrease in energy at higher trophic levels

(b) Defficient food supply

(c) Polluted air

(d) Water

Sol. (a) 

Q.14 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

(d) Plants convert solar energy into chemical energy

Sol. (b) 

Q.15 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)

(d) (i) and (iv)

Sol. (c) 

Q.16 The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about

(a) 1%

(b) 5%

(c) 8%

(d) 10%

Sol. (a) 

Q.17 In the given Figure 15.1 the various trophic levels are shown in a pyramid. At which trophic level is maximum energy available?

(a) T4

(b) T2

(c) T1

(d) T3

Sol. (c) 

Q.18 What will happen if deer is missing in the food chain given below?

Grass → Deer → Tiger

(a) The population of tiger increases

(b) The population of grass decreases

(c) Tiger will start eating grass

(d) The population of tiger decreases and the population of grass increases

Sol. (d) 

Q.19 The decomposers in an ecosystem

(a) Convert inorganic material, to simpler forms

(b) Convert organic material to inorganic forms

(c) Convert inorganic materials into organic compounds

(d) Do not breakdown organic compounds

Sol. (b) 

Q.20 If a grass hopper is eaten by a frog, then the energy transfer will be from

(a) producer to decomposer

(b) Producer to primary consumer

(c) Primary consumer to secondary consumer

(d) Secondary consumer to primary consumer

Sol. (c) 

Q.21 Disposable plastic plates should not be used because

(a) they are made of materials with light weight

(b) they are made of toxic materials

(c) they are made of biodegradable materials

(d) they are made of non-biodegradable materials

Sol. (d)