Decomposers, decay rates and recycling nutrients
10th grade (Year 11 in England) · 16 questions · Common Core: NGSS.HS-LS2-3, NGSS.HS-LS2-5 · England: GCSE Combined Science: Ecology
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Question 1
A bag of grass clippings had a mass of 120 g. After 10 days in a compost bin its mass was 105 g. What was the mean rate of decay, in g per day?
Answer
Question 2
What role do decomposers play in the carbon cycle?
- A. They photosynthesise
- B. They respire, releasing carbon dioxide from dead material back into the air
- C. They lock carbon away forever
- D. They turn carbon into oxygen
Question 3
Decay: which statement is NOT true?
- A. Decay is faster when it is warm and moist.
- B. Decay is fastest when everything is frozen.
- C. Decomposers include bacteria and fungi.
- D. Compost can be used as a natural fertiliser.
Question 4
A bag of grass clippings had a mass of 150 g. After 5 days in a compost bin its mass was 140 g. What was the mean rate of decay, in g per day?
Answer
Question 5
What role do decomposers play in the carbon cycle?
- A. They photosynthesise
- B. They lock carbon away forever
- C. They turn carbon into oxygen
- D. They respire, releasing carbon dioxide from dead material back into the air
Question 6
Decay: which statement is NOT true?
- A. Compost can be used as a natural fertiliser.
- B. Decomposers create new atoms of carbon.
- C. Decay is faster when it is warm and moist.
- D. Decomposers include bacteria and fungi.
Question 7
A bag of grass clippings had a mass of 150 g. After 5 days in a compost bin its mass was 142.5 g. What was the mean rate of decay, in g per day?
Answer
Question 8
Why do gardeners turn their compost heaps regularly?
- A. to cool the heap to 0 °C
- B. to kill all the microorganisms
- C. to add oxygen for the decomposers' aerobic respiration
- D. to dry it out completely
Question 9
Decay: which statement is NOT true?
- A. Decay returns mineral ions to the soil.
- B. Decay is faster when it is warm and moist.
- C. Decomposers need no oxygen at all.
- D. Compost can be used as a natural fertiliser.
Question 10
A bag of grass clippings had a mass of 200 g. After 5 days in a compost bin its mass was 190 g. What was the mean rate of decay, in g per day?
Answer
Question 11
A biogas generator lets waste decay without oxygen. What useful gas does it produce?
- A. helium
- B. oxygen
- C. methane, which can be burned as a fuel
- D. nitrogen
Question 12
Decay: which statement is NOT true?
- A. Decay is fastest when everything is frozen.
- B. Decay is faster when it is warm and moist.
- C. Decomposers include bacteria and fungi.
- D. Compost can be used as a natural fertiliser.
Question 13
A bag of grass clippings had a mass of 150 g. After 5 days in a compost bin its mass was 142.5 g. What was the mean rate of decay, in g per day?
Answer
Question 14
Why do gardeners turn their compost heaps regularly?
- A. to add oxygen for the decomposers' aerobic respiration
- B. to dry it out completely
- C. to kill all the microorganisms
- D. to cool the heap to 0 °C
Question 15
Decay: which statement is NOT true?
- A. Decay returns mineral ions to the soil.
- B. Decomposers include bacteria and fungi.
- C. Decay is faster when it is warm and moist.
- D. Decay is fastest when everything is frozen.
Question 16
A bag of grass clippings had a mass of 120 g. After 20 days in a compost bin its mass was 60 g. What was the mean rate of decay, in g per day?
Answer
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