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Biology for IGCSE & O level - Organisms And Their Environment (Section 4)

1
What term describes the sequence of organisms where each organism feeds on the one below it?
Answer
(C)
Food chain
2
Which of the following is part of the carbon cycle?
Answer
(B)
The movement of carbon dioxide.
3
How is energy transferred in a food chain?
Answer
(B)
From producers to consumers.
4
What does a pyramid of biomass represent?
Answer
(B)
The total weight of living material at each trophic level.
5
What happens to energy as it moves from one trophic level to the next in a food chain?
Answer
(C)
The energy decreases.
6
What is the term for the organisms that eat other organisms?
Answer
(B)
Consumers
7
What process converts ammonia into nitrates?
Answer
(B)
Nitrification
8
What process removes carbon dioxide from the atmosphere?
Answer
(C)
Photosynthesis
9
Which organisms are involved in the nitrogen cycle?
Answer
A
B
C
D
10
What is the role of decomposers in an ecosystem?
Answer
(B)
They break down dead organisms.
11
What role does decomposition play in the nutrient cycle?
Answer
(B)
Releasing nutrients from dead organisms.
12
Which organisms are able to produce their own food through photosynthesis?
Answer
(C)
Producers
13
How is carbon dioxide removed from the atmosphere?
Answer
(B)
Through photosynthesis.
14
Which of the following statements correctly describe the role of nitrogen-fixing bacteria?
Answer
A
B
15
What are the steps involved in the nitrogen cycle?
Answer
A
B
C
16
What is the primary function of the carbon cycle?
Answer
(C)
To recycle carbon through the ecosystem.
17
What is the main form of nitrogen that plants can use?
Answer
(C)
Nitrates
18
Which of the following organisms are classified as primary consumers?
Answer
(C)
Herbivores
19
How is energy transferred between trophic levels?
Answer
(C)
Through feeding relationships.
20
Why might a pyramid of numbers be inverted?
Answer
(A)
If the producers are very large organisms (e.g., trees).
21
What are the advantages of using a pyramid of biomass instead of a pyramid of numbers?
Answer
(C)
Pyramids of biomass account for the size of organisms.
22
What is the primary source of nitrogen for plants?
Answer
(B)
Nitrates in the soil.
23
In what form do plants primarily take up nitrogen?
Answer
(C)
Nitrates
24
What are the consequences of excess fertilizer runoff?
Answer
A
B
C
25
What role do decomposers play in the carbon cycle?
Answer
(B)
They release carbon dioxide into the atmosphere.
26
Which of the following are examples of producers?
Answer
(C)
Plants
27
What do herbivores consume?
Answer
(B)
Plants
28
What is the process that converts ammonia into nitrates?
Answer
(B)
Nitrification
29
Which process releases carbon dioxide into the atmosphere?
Answer
(B)
Respiration
30
Which is a key difference between a pyramid of numbers and a pyramid of biomass?
Answer
(D)
Pyramid of numbers does not account for the size, pyramid of biomass does.
31
What do the arrows in a food chain represent?
Answer
(C)
The direction of energy flow.
32
What is a key difference between pyramids of numbers and pyramids of biomass?
Answer
(B)
Pyramids of biomass account for the size or mass of the organisms.
33
What is a food web?
Answer
(C)
A network of interconnected food chains.
34
What is a significant source of nitrogen in the atmosphere?
Answer
(C)
Nitrogen gas
35
What is the role of sunlight in an ecosystem?
Answer
(B)
To provide energy for the ecosystem.
36
What is the role of legumes in the nitrogen cycle?
Answer
(B)
They host nitrogen-fixing bacteria in their roots.
37
What do food chains and food webs illustrate?
Answer
(A)
The flow of energy in an ecosystem.
38
What is a food web?
Answer
(C)
A network of interconnected food chains.
39
What is the main product of photosynthesis?
Answer
(B)
Oxygen
40
Which of the following organisms are consumers?
Answer
(B)
Animals
41
Which of the following is an example of a nutrient cycle?
Answer
(D)
All of the above
42
What is the main process by which carbon is removed from the atmosphere?
Answer
(C)
Photosynthesis
43
Which organisms are the source of energy for a food chain?
Answer
(B)
Producers
44
What are some of the key steps in the nitrogen cycle?
Answer
A
B
C
45
How does energy flow through a food chain?
Answer
(C)
From producers to consumers.
46
Which organisms contribute directly to the process of decomposition?
Answer
(C)
Decomposers
47
What is the primary source of energy for most ecosystems?
Answer
(B)
Sunlight
48
Why are pyramids of numbers sometimes not a good representation of energy flow?
Answer
(B)
They do not consider the size or biomass of organisms.
49
What is the role of producers in an ecosystem?
Answer
(C)
They make their own food using sunlight.
50
Which of the following are examples of greenhouse gases?
Answer
A
C