AP Environmental Science Practice Quiz: The Carbon Cycle
Written by AP Content Team, Verified for 2026 AP Exams, Last updated: May 2026
Test your understanding with short quizzes. This quiz has 11 questions to check your progress.
Question 1 of 11
All Questions (11)
A) The storage of carbon in plants and animals over millions of years.
B) The movement of carbon atoms and molecules between sources and sinks.
C) The process of converting atmospheric carbon into fossil fuels.
D) The exchange of carbon dioxide between photosynthesis and cellular respiration.
Correct Answer: B
The provided content explicitly states, 'The carbon cycle is the movement of atoms and molecules containing the element carbon between sources and sinks.'
A) Decomposition and the burning of fossil fuels
B) Long-term storage and short-term storage
C) Photosynthesis and cellular respiration
D) Movement between sources and sinks
Correct Answer: C
The text states, 'Carbon cycles between photosynthesis and cellular respiration in living things.'
A) Some reservoirs are made of living things, while others are non-living.
B) Some reservoirs are sources, while others are exclusively sinks.
C) Some reservoirs hold carbon for long periods, while others hold it for short periods.
D) Some reservoirs are involved in decomposition, while others are involved in photosynthesis.
Correct Answer: C
The content specifies that 'Some of the reservoirs in which carbon compounds occur hold those compounds for long periods, while some hold them for relatively short periods.'
A) It creates new carbon atoms in the atmosphere.
B) It moves carbon stored over millions of years into the atmosphere as carbon dioxide.
C) It slows down the rate of plant and animal decomposition.
D) It increases the amount of carbon stored in long-term reservoirs.
Correct Answer: B
The text states, 'The burning of fossil fuels quickly moves that stored carbon into atmospheric carbon, in the form of carbon dioxide.'
A) Cellular respiration in living things
B) The movement of carbon between sources and sinks
C) Photosynthesis by ancient plants
D) The decomposition of plants and animals
Correct Answer: D
The provided content says, 'Plant and animal decomposition has led to the storage of carbon over millions of years.' The text then links this stored carbon to fossil fuels.
A) long-term reservoir to a short-term reservoir.
B) sink to a source.
C) reservoir of living things to an atmospheric reservoir.
D) reservoir in the atmosphere to a reservoir in living things.
Correct Answer: D
The text states that carbon cycles between photosynthesis and cellular respiration in living things. Photosynthesis is the process by which living plants take in atmospheric carbon (in the form of carbon dioxide) and convert it into organic compounds, thus moving it from the atmosphere to a living organism.
A) The storage of carbon over millions of years
B) The interaction between long-term reservoirs
C) The cycling of carbon via photosynthesis and cellular respiration
D) The decomposition of ancient plant and animal matter
Correct Answer: C
The text describes the storage of carbon from decomposition as taking 'millions of years.' In contrast, it mentions the cycling of carbon between photosynthesis and respiration in 'living things,' which is a relatively short-term, or rapid, process.
A) Two different short-term reservoirs
B) A long-term storage reservoir and the atmospheric reservoir
C) Two different long-term storage reservoirs
D) A reservoir of living organisms and a long-term storage reservoir
Correct Answer: B
Fossil fuels are the result of carbon storage 'over millions of years,' making them a long-term reservoir. The text states that burning them moves this carbon into 'atmospheric carbon.' This represents a movement from a long-term reservoir to the atmospheric reservoir.
A) Atmospheric carbon
B) Carbon compounds in living things
C) Carbon dioxide
D) Fossil fuels
Correct Answer: D
The text directly connects the two ideas: 'Plant and animal decomposition has led to the storage of carbon over millions of years. The burning of fossil fuels quickly moves that stored carbon...' This implies that the stored carbon is in the form of fossil fuels.
A) Plant and animal decomposition has led to the storage of carbon over millions of years.
B) Some reservoirs hold carbon compounds for long periods.
C) Carbon cycles between photosynthesis and cellular respiration in living things.
D) The carbon cycle is the movement of atoms between sources and sinks.
Correct Answer: C
The student's claim is that all movement is slow. The statement 'Carbon cycles between photosynthesis and cellular respiration in living things' describes a biological process that occurs on a very short timescale compared to the millions of years it takes for fossil fuel formation, directly refuting the claim.
A) Only living things are part of the carbon cycle.
B) The carbon cycle involves reservoir interactions over different time scales.
C) All carbon is eventually stored as fossil fuels.
D) Human activity is the only driver of the carbon cycle.
Correct Answer: B
The text covers short-term cycling (photosynthesis/respiration), long-term storage (decomposition over millions of years), and the quick release from that storage (burning fossil fuels). This variety demonstrates that the carbon cycle involves different components operating on vastly different time scales, as supported by the statement that some reservoirs hold carbon for long periods and some for short periods.