Online Test — Our Environment
15 Questions • 15 min • Chapter MCQ
15:00
Question 1 of 15
A self-contained unit of living organisms interacting with their non-living surroundings is an:
Ecosystem
Atom
Organ
Tissue
Explanation: An ecosystem is the interacting unit of living and non-living components.
Question 2 of 15
Sunlight, water and soil in an ecosystem are its ___ components.
Biotic
Abiotic
Producer
Consumer
Explanation: Non-living physical factors are the abiotic components.
Question 3 of 15
Organisms that make their own food in an ecosystem are:
Producers
Consumers
Decomposers
Predators
Explanation: Green plants are producers; they make their own food.
Question 4 of 15
Bacteria and fungi that break down dead matter are:
Producers
Herbivores
Decomposers
Carnivores
Explanation: Decomposers break down dead organisms and recycle nutrients.
Question 5 of 15
A sequence showing who eats whom, such as grass to deer to tiger, is a:
Food web
Food chain
Trophic web
Life cycle
Explanation: A linear who-eats-whom sequence is a food chain.
Question 6 of 15
Each step in a food chain is called a:
Trophic level
Producer
Decomposer
Niche
Explanation: Each feeding step is a trophic level.
Question 7 of 15
Many interconnected food chains form a:
Food web
Single chain
Trophic level
Pyramid base
Explanation: Interlinked food chains make a food web.
Question 8 of 15
The ultimate source of energy for almost all ecosystems is the:
Soil
Sun
Wind
Decomposers
Explanation: The Sun's energy is captured by producers and flows through the ecosystem.
Question 9 of 15
The flow of energy through an ecosystem is:
Unidirectional
Two-way
Circular
Reversible
Explanation: Energy flows one way and is lost as heat at each step.
Question 10 of 15
According to the ten per cent law, energy passed to the next trophic level is about:
10%
90%
50%
100%
Explanation: Only about 10% of energy moves to the next level; ~90% is lost.
Question 11 of 15
Food chains are usually short because:
Much energy is lost at each level
Animals refuse to eat
Plants are few
Energy increases each step
Explanation: Heavy energy loss at each level limits chains to 4-5 trophic levels.
Question 12 of 15
The ozone layer protects living things by absorbing harmful:
UV rays
Visible light
Sound
Heat from soil
Explanation: Ozone absorbs the Sun's harmful ultraviolet rays.
Question 13 of 15
The ozone layer is damaged mainly by:
Oxygen
CFCs (chlorofluorocarbons)
Carbon dioxide only
Water vapour
Explanation: CFCs are man-made chemicals that deplete the ozone layer.
Question 14 of 15
Which of these is a biodegradable waste?
Plastic bag
Glass bottle
Vegetable peels
Aluminium can
Explanation: Vegetable peels are broken down by decomposers, so they are biodegradable.
Question 15 of 15
Separating biodegradable and non-biodegradable wastes before disposal is called:
Segregation
Pollution
Photosynthesis
Respiration
Explanation: Segregation separates wastes so each can be treated appropriately.