Biology for IGCSE & O level - Organisms And Their Environment (Section 6)
1
Answer(C)
A complex network of interconnected food chains.
2
Which processes are involved in the nitrogen cycle?
3
Which of the following are processes in the carbon cycle?
4
What are the key roles of the following in the nitrogen cycle?
5
What is the term for the position an organism occupies in a food chain or food web?
6
What role do decomposers play in the carbon cycle?
Answer(B)
Releasing carbon dioxide.
7
What is the difference between primary and secondary consumers?
Answer(A)
Primary consumers eat producers; secondary consumers eat primary consumers.
8
What is meant by the term 'trophic level'?
Answer(C)
The position an organism occupies in a food chain.
9
Why are decomposers essential in an ecosystem?
10
What is the primary source of carbon in the carbon cycle?
11
What is a pyramid of biomass?
Answer(A)
A representation of the total weight of organisms at each trophic level.
12
Answer(B)
A complex network of interconnected food chains.
13
What do pyramids of biomass measure?
Answer(B)
The total weight of living material at each trophic level.
14
Which of the following is a major source of carbon dioxide in the atmosphere?
15
Why is there a loss of energy between trophic levels?
Answer(B)
Because energy is used for life processes and lost as heat.
16
What is the main difference between autotrophs and heterotrophs?
Answer(A)
Autotrophs make their own food; heterotrophs consume other organisms.
17
What is a food web made up of?
Answer(B)
A collection of interacting food chains.
