Biology for IGCSE & O level - Organisms And Their Environment (Section 5)
1
What are the roles of the different bacteria involved in the nitrogen cycle?
Answer
A
B
C
2
What does a food chain illustrate?
Answer
(B)
The feeding relationships between organisms.
3
Why do food chains typically have a limited number of trophic levels?
Answer
(A)
Because there is too much energy loss at each level.
4
What does a pyramid of biomass represent?
Answer
(B)
The weight of living material at each trophic level.
5
What is the role of photosynthesis in the carbon cycle?
Answer
(B)
Absorbing carbon dioxide.
6
What are the potential limitations of using pyramids of numbers to represent an ecosystem?
Answer
(B)
They may not accurately show the flow of energy in an ecosystem.
7
What are the main processes involved in the carbon cycle?
Answer
A
B
C
8
What is the role of decomposers in an ecosystem?
Answer
(C)
To break down dead organic matter and recycle nutrients.
9
What is the term for the conversion of atmospheric nitrogen into a usable form?
Answer
(C)
Nitrogen fixation
10
What is the role of consumers in an ecosystem?
Answer
(C)
To eat other organisms.
11
What is the main process that removes carbon dioxide from the atmosphere?
Answer
(C)
Photosynthesis
12
What is the primary role of decomposers in an ecosystem?
Answer
(B)
To break down dead organisms and waste.
13
What does a pyramid of numbers show?
Answer
(A)
The number of organisms at each trophic level.
14
What are the main processes in the carbon cycle?
Answer
A
B
C
15
Which of the following statements best describes the flow of energy in a food chain?
Answer
(B)
Energy flows unidirectionally from producers to consumers and eventually to decomposers.
16
What do food webs show?
Answer
(C)
The feeding relationships within a community.
17
Which of the following organisms are producers?
Answer
(B)
A tree
18
What are the organisms that break down dead organisms?
Answer
(C)
Decomposers
19
What type of consumer eats plants?
Answer
(B)
Herbivore
20
What are the negative impacts of deforestation?
Answer
A
B
D
21
What happens to energy as it moves through a food chain?
Answer
(C)
It decreases.
22
Which organisms play a role in decomposition?
Answer
A
B
23
What is the difference between a food chain and a food web?
Answer
(B)
A food chain shows the flow of energy from one organism to another, while a food web shows multiple interconnected food chains.
24
Which of the following is the most accurate representation of the direction of energy transfer in an ecosystem?
Answer
(B)
From producers to consumers and then decomposers
25
What is the main goal of decomposition in an ecosystem?
Answer
(C)
To recycle nutrients.
26
What process converts nitrogen gas into usable forms?
Answer
(D)
Nitrogen fixation
27
What is the role of decomposers in an ecosystem?
Answer
(B)
To break down dead organisms and recycle nutrients.
28
What are the organisms that eat both plants and animals called?
Answer
(C)
Omnivores
29
Which of the following is a key component of the carbon cycle?
Answer
(C)
The movement of carbon.
30
What is the main limiting factor of the number of trophic levels in a food chain?
Answer
(C)
The amount of energy lost at each level
31
Which of the following is a factor that limits the length of a food chain?
Answer
(C)
The amount of energy transferred between trophic levels.
32
What is the role of producers in an ecosystem?
Answer
(C)
They make their own food using sunlight.
33
Why are pyramids of numbers often not the best representation of an ecosystem's energy flow?
Answer
(B)
They fail to account for the size or biomass of the organisms at each trophic level.
34
What is a major difference between the carbon and nitrogen cycles?
Answer
(C)
The carbon cycle involves the conversion of carbon to different molecules, while the nitrogen cycle involves the conversion of nitrogen to different molecules.
35
What is the primary role of photosynthesis in the carbon cycle?
Answer
(B)
Absorbing carbon dioxide.
36
Which of the following is a major component of the nitrogen cycle?
Answer
(C)
The movement of nitrogen.
37
What is the purpose of a food web?
Answer
(C)
To show the flow of energy between organisms in a complex network.
38
What type of organisms eat other organisms for energy?
Answer
(B)
Consumers
39
Which of the following human activities have a significant impact on the carbon cycle?
Answer
A
B
D
40
Which term describes the sequence of who eats whom in an ecosystem?
Answer
(B)
Food chain
41
What do the arrows in a food chain represent?
Answer
(A)
The movement of energy.
42
What term is used to describe the position of an organism in a food chain or food web?
Answer
(C)
Trophic level
43
What is the role of nitrification in the nitrogen cycle?
Answer
(B)
Converting ammonia into nitrates.
44
What do the arrows in a food chain represent?
Answer
(A)
The movement of energy.
45
What are the primary components of an ecosystem?
Answer
(D)
Producers, consumers, decomposers, and abiotic factors.
46
What type of consumer eats other animals?
Answer
(B)
Carnivore
47
What process is involved in the conversion of atmospheric nitrogen to ammonia?
Answer
(D)
Nitrogen fixation
48
What is the main source of energy in most ecosystems?
Answer
(C)
The sun
49
How does energy flow through an ecosystem?
Answer
(B)
From producers to consumers to decomposers.
50
What process releases carbon dioxide into the atmosphere?
