Our Environment
Question 1.
Assertion: Vegetarian food habit is more beneficial to organisms.
Reason: Only 10% energy is available as food from one trophic level to next.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
(e) Both A and R are false.
Answer
(a) Both A and R are true and R is the correct explanation of A.
Question 2.
In natural ecosystems, decomposers include-
(a) only bacteria and fungi
(b) only microscopic animals
(c) herbivores and carnivores
(d) both (b) and (c)
Answer
(a) only bacteria and fungi
Question 3.
The percentage of solar radiation absorbed by all the green plants for the process of
photosynthesis is about-
(a) 1%
(b) 8%
(c) 5%
(d) 10%
Answer
(a) 1%
Question 4.
The second trophic level is always of-
(a) herbivores
(b) autotrophs
(c) carnivores
(c) producers
Answer
(a) herbivores
Question 5.
The decomposers in an ecosystem-
(a) convert organic material to inorganic forms
(b) convert inorganic material to simpler forms
(c) convert inorganic material into organic compound
(d) do not break down organic compound
Answer
(a) convert organic material to inorganic forms
Question 6.
Which of the following is an abiotic component of an ecosystem?
(a) Humus
(b) Bacteria
(c) Plants
(d) Fungi
Answer
(a) Humus
Question 7.
What will happen if all the deer are killed in the given food chain?
Grass → Deer → Lion
(a) The population of grass decreases.
(b) The population of lions increases.
(c) The population of lions remains unchanged.
(d) The population of lions decreases and grass increases.
Answer
(d) The population of lions decreases and grass increases.
Question 8.
Which of the following is not a terrestrial ecosystem-
(a) forest
(b) desert
(c) aquarium
(d) grassland
Answer
(c) aquarium
Question 9.
In the garden ecosystem, which of the following are producers?
(a) Insects
(b) Snakes
(c) Grasses
(d) Rabbits
Answer
(c) Grasses
Question 10.
Which of the following is biodegradable?
(a) Plastic mugs
(b) Leather belts
(c) Silver foil
(d) Iron nails
Answer
(b) Leather belts
Question 11.
Which of the following is an autotroph?
(a) Lion
(b) Insect
(c) Tree
(d) Mushroom
Answer
(c) Tree
Question 12.
Which of the following is a logical sequence of food chain
(a) producer → consumer → decomposer
(b) producer → decomposer → consumer
(c) consumer → producer → decomposer
(d) decomposer → producer → consumer
Answer
(a) producer → consumer → decomposer
Question 13.
A food chain comprising birds, green plants, fish and man. The concentration of harmful chemical
entering the food chain will be maximum in
(a) green plants
(b) man
(c) birds
(d) fish
Answer
(b) man
Question 14.
Ozone layer is damaged by-
(a) methane
(b) carbon-dioxide
(c) Sulphur-dioxide
(d) CFCs
Answer
(d) CFCs
Question 15.
In an ecosystem, herbivores represent
(a) producers
(b) primary consumers
(c) secondary consumers
(d) decomposers
Answer
(b) primary consumers
Question 16.
Which one of the following will undergo fastest bio-degradation?
(a) Mango seed
(b) Wood
(c) Mango peel
(d) Mango pulp
Answer
(d) Mango pulp
Question 17.
Assertion: Biodegradable waste and non biodegradable waste should be discarded separately,
Reason: Biodegradable waste are not harmful.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
(e) Both A and R are false.
Answer
(c) A is true but R is false.
Question 18.
Assertion: Ozone layer is getting depleted at upper atmosphere which is a cause of concern.
Reason: CFC reacts with ozone and breaks it.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
(e) Both A and R are false.
Answer
(a) Both A and R are true and R is the correct explanation of A.
Question 19.
Flow of energy in an ecosystem is always-
(a) unidirectional
(b) bidirectional
(c) multidirectional
(d) no specific direction.
Answer
(a) unidirectional
Question 20.
The ecosystem of earth is known as-
(a) biome
(b) community
(c) biosphere
(c) association
Answer
(c) biosphere
Question 21.
Which of the two in the following sets belong to the same trophic level?
(a) Grass : Grasshopper
(b) Goat : Spider
(c) Hawk : Rat
(d) Frog : Lizard
Answer
(d) Frog : Lizard
Question 22.
Acid rain is caused by the oxides of
(a) carbon
(b) nitrogen only
(c) sulphur only
(d) sulphur and nitrogen
Answer
(d) sulphur and nitrogen
Question 23.
The depletion of the ozone layer causes
(a) global wanning
(b) earthquakes
(c) increased UV radiations
(d) acid rain
Answer
(c) increased UV radiations
Question 24.
Which one of the following pairs belong to the category of primary consumers?
(a) Eagle and snake
(b) Grasshoppers & cattle
(c) Snake and frog
(d) Water beetles & fish
Answer
(b) Grasshoppers & cattle
Question 25.
Which of the following is biodegradable?
(a) Aluminium can
(b) Polythene bag
(c) Cowdung
(d) DDT
Answer
(c) Cowdung
Question 26.
Which of the following is non-biodegradable-
(a) paper
(b) wood
(c) cloth
(d) plastic
Answer
(d) plastic
Question 27.
Trophic level in an ecosystem represents
(a) oxygen level
(b) water level
(c) energy level
(d) salt level
Answer
(c) energy level
Question 28.
Excessive exposure to ultraviolet radiation causes
(a) inflammation of liver
(b) cancer of skin
(c) damage to the lungs
(d) jaundice
Answer
(b) cancer of skin
Question 29.
Which of the following limits the number of trophic levels in a food chain?
(a) water
(b) polluted air
(c) deficient food supply
(d) decrease in energy at higher trophic levels
Answer
(d) decrease in energy at higher trophic levels
Question 30.
A food chain always starts with
(a) respiration
(b) photosynthesis
(c) decay
(d) nitrogen fixation
Answer
(b) photosynthesis
Question 31.
Which of the following is non- biodegradable?
(a) Wool
(b) Nylon
(c) Animal bones
(d) Tea leaves
Answer
(b) Nylon
Question 32.
First link in any food chain is usually green plants because
(a) they are widely distributed
(b) they are fixed at one place in the soil
(c) they alone have the capacity to synthesise food using sunlight
(d) there are more herbivores than carnivores
Answer
(c) they alone have the capacity to synthesise food using sunlight