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Class 10 Our Environment worksheet
CBSE Science. Food chains, the 10 per cent law, biological magnification, waste, ozone. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
In the food chain grass → deer → lion, the deer is a:
- primary consumer (herbivore)
- tertiary consumer
- producer
- secondary consumer
Answer
(a) primary consumer (herbivore)
trophic level 2
- 2.
In the food chain wheat → rat → owl, the producers hold 2,000 J of energy. By the 10 per cent law, how much reaches the owl?
- 2 J
- 200 J
- 1,800 J
- 20 J
Answer
(d) 20 J
2,000 × (1/10)²
- 3.
Organisms that make their own food using sunlight are called:
- decomposers
- parasites
- consumers
- producers
Answer
(d) producers
Section B · short answer
- 4.
In the food chain algae → water flea → small fish → kingfisher, the producers hold 20,000 kJ. Using the 10 per cent law, find the energy at each of the other levels.
Answer
water flea: 2,000 kJ; small fish: 200 kJ; kingfisher: 20 kJ
divide by 10 at each step
- 5.
Name the trophic level of each organism in the food chain leaves → caterpillar → sparrow → hawk.
Answer
leaves: producer; caterpillar: primary consumer (herbivore); sparrow: secondary consumer; hawk: tertiary consumer
Section C · long answer
- 6.
Explain the flow of energy in an ecosystem using the 10 per cent law.
Answer
Producers capture about 1% of the sunlight falling on them and change it into chemical energy. Herbivores get about 10% of the energy in the plants they eat; carnivores get about 10% of that. The rest is used in life processes or lost as heat. So energy flows in one direction and decreases at each level, which limits food chains to 3–4 levels.
Fresh sheets for your child
In the app, every Our Environment sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
Coming soon for Android and iPhone.