Vidaara.orgClass 10 · Mathematics
CodeVID-M10-WS
Our Environment — Practice Worksheet
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- All questions are compulsory.
- Choose the correct option (A, B, C or D) for each question.
- The answer key is at the end — try the paper first!
Section A — Multiple Choice (1 mark each)
15 × 1 = 15 marks
1.
A self-contained unit of living organisms interacting with their non-living surroundings is an:
- A.Ecosystem
- B.Atom
- C.Organ
- D.Tissue
2.
Sunlight, water and soil in an ecosystem are its ___ components.
- A.Biotic
- B.Abiotic
- C.Producer
- D.Consumer
3.
Organisms that make their own food in an ecosystem are:
- A.Producers
- B.Consumers
- C.Decomposers
- D.Predators
4.
Bacteria and fungi that break down dead matter are:
- A.Producers
- B.Herbivores
- C.Decomposers
- D.Carnivores
5.
A sequence showing who eats whom, such as grass to deer to tiger, is a:
- A.Food web
- B.Food chain
- C.Trophic web
- D.Life cycle
6.
Each step in a food chain is called a:
- A.Trophic level
- B.Producer
- C.Decomposer
- D.Niche
7.
Many interconnected food chains form a:
- A.Food web
- B.Single chain
- C.Trophic level
- D.Pyramid base
8.
The ultimate source of energy for almost all ecosystems is the:
- A.Soil
- B.Sun
- C.Wind
- D.Decomposers
9.
The flow of energy through an ecosystem is:
- A.Unidirectional
- B.Two-way
- C.Circular
- D.Reversible
10.
According to the ten per cent law, energy passed to the next trophic level is about:
- A.10%
- B.90%
- C.50%
- D.100%
11.
Food chains are usually short because:
- A.Much energy is lost at each level
- B.Animals refuse to eat
- C.Plants are few
- D.Energy increases each step
12.
The ozone layer protects living things by absorbing harmful:
- A.UV rays
- B.Visible light
- C.Sound
- D.Heat from soil
13.
The ozone layer is damaged mainly by:
- A.Oxygen
- B.CFCs (chlorofluorocarbons)
- C.Carbon dioxide only
- D.Water vapour
14.
Which of these is a biodegradable waste?
- A.Plastic bag
- B.Glass bottle
- C.Vegetable peels
- D.Aluminium can
15.
Separating biodegradable and non-biodegradable wastes before disposal is called:
- A.Segregation
- B.Pollution
- C.Photosynthesis
- D.Respiration
Section B — Challenge / Olympiad (2 marks each)
6 × 2 = 12 marks
16.
If all the decomposers in an ecosystem suddenly disappeared, the most likely result would be:
- A.Dead matter piles up and nutrients are not recycled
- B.More energy at every level
- C.Faster plant growth
- D.No change at all
17.
In the chain grass (10,000 J) to deer to tiger, the tiger receives about:
- A.100 J
- B.1000 J
- C.10,000 J
- D.5000 J
18.
Harmful chemicals like pesticides become most concentrated in the bodies of top carnivores. This happens because:
- A.The chemicals are passed up and build up along the food chain (biomagnification)
- B.Top carnivores eat plants only
- C.The chemicals disappear
- D.Producers store the most
19.
Why is there usually a far smaller number of top carnivores than producers in an ecosystem?
- A.Only a small fraction of energy reaches the top levels
- B.Carnivores never reproduce
- C.Producers eat carnivores
- D.There is no Sun
20.
A 'hole' in the ozone layer is a serious concern mainly because it lets in more:
- A.UV radiation, raising skin-cancer risk
- B.Oxygen
- C.Rain
- D.Sound
21.
Using cloth bags and composting kitchen waste at home helps the environment mainly by:
- A.Reducing non-biodegradable waste and recycling nutrients
- B.Increasing plastic use
- C.Depleting ozone
- D.Adding CFCs
Answer Key
Section A — Multiple Choice (1 mark each)
- (A) Ecosystem
- (B) Abiotic
- (A) Producers
- (C) Decomposers
- (B) Food chain
- (A) Trophic level
- (A) Food web
- (B) Sun
- (A) Unidirectional
- (A) 10%
- (A) Much energy is lost at each level
- (A) UV rays
- (B) CFCs (chlorofluorocarbons)
- (C) Vegetable peels
- (A) Segregation
Section B — Challenge / Olympiad (2 marks each)
- (A) Dead matter piles up and nutrients are not recycled
- (A) 100 J
- (A) The chemicals are passed up and build up along the food chain (biomagnification)
- (A) Only a small fraction of energy reaches the top levels
- (A) UV radiation, raising skin-cancer risk
- (A) Reducing non-biodegradable waste and recycling nutrients
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