10th grade ecosystems and food chains

Question 1

Decay: which statement is NOT true?

• A. Decay returns mineral ions to the soil.
• B. Decomposers include bacteria and fungi.
• C. Decomposers create new atoms of carbon.
• D. Decay is faster when it is warm and moist.

Question 2

A bag of grass clippings had a mass of 100 g. After 12 days in a compost bin its mass was 82 g. What was the mean rate of decay, in g per day?

Answer 

Question 3

Which action helps increase biodiversity on farmland?

• A. removing all hedges
• B. growing one crop everywhere
• C. spraying more insecticide
• D. planting hedgerows and leaving wildflower field margins

Question 4

Biodiversity: which statement is NOT true?

• A. Global warming is changing where some species can live.
• B. Human activity has no effect on extinction rates.
• C. Breeding programmes can help protect endangered species.
• D. Deforestation reduces biodiversity and adds carbon dioxide to the air.

Question 5

The mean number of buttercups in a 0.25 m² quadrat is 15. The field is 200 m². Estimate the number of buttercups in the field.

Answer 

Question 6

A survey found 200 breeding pairs of a bird species in 2010 and 160 in 2024. What was the percentage decrease?

Answer %

Question 7

How can you see how plant species change from a hedge to the middle of a field?

• A. Count only the tallest plants
• B. Sample at night
• C. Place quadrats at regular intervals along a transect line
• D. Place one quadrat by the hedge only

Question 8

Why do gardeners turn their compost heaps regularly?

• A. to kill all the microorganisms
• B. to dry it out completely
• C. to add oxygen for the decomposers' aerobic respiration
• D. to cool the heap to 0 °C

Question 9

Five 1 m² quadrats contained these numbers of daisies: 7, 7, 5, 2, 6. What is the mean number of daisies per quadrat?

Answer 

Question 10

Decay: which statement is NOT true?

• A. Compost can be used as a natural fertiliser.
• B. Decay returns mineral ions to the soil.
• C. Decomposers need no oxygen at all.
• D. Decay is faster when it is warm and moist.

Question 11

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 12

Rewilding projects reintroduce species such as beavers. What can beavers do for an ecosystem?

• A. They remove all fish
• B. They have no effect
• C. Their dams create wetlands that support many other species and reduce flooding downstream
• D. They make rivers flow faster

Question 13

Biodiversity: which statement is NOT true?

• A. Biodiversity means the number of individuals of one species.
• B. Global warming is changing where some species can live.
• C. Fertiliser running into lakes can cause algae to grow and oxygen to fall.
• D. Breeding programmes can help protect endangered species.

Question 14

The mean number of buttercups in a 0.25 m² quadrat is 10. The field is 500 m². Estimate the number of buttercups in the field.

Answer 

Question 15

A survey found 120 hedgehogs counted in a survey in 2010 and 72 in 2024. What was the percentage decrease?

Answer %

Question 16

Which is a biotic factor?

• A. temperature
• B. a new predator arriving
• C. soil pH
• D. carbon dioxide level