1

1 Carbon dioxide enters the leaves of plants and is used by the plant during photosynthesis to make —

A nitrogen.

B hydrogen.

C glucose.

D water.

2 What role do decomposers have in contributing to the survival of other organisms in their environments? Decomposers —

A use sunlight to make food for other organisms

B release nutrients that plants use into the soil.

C exhale oxygen through the process of respiration.

D give off water vapor into the air during transpiration.

Cycling of MatterMatter and Energy

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3 Look at the chart provided.

For each temperature and over each one week time period, determine the one week time period where the greatest decomposition of matter occurred. Record the height of the pile of leaves after undergoing its greatest decomposition. Record your answer in the grid provided.

Cycling of MatterMatter and Energy

Temperature °C

Week 1Height of a

pile of leaves (cm)

Week 2Height of a

pile of leaves (cm)

Week 3Height of a

pile of leaves (cm)

Week 4Height of a

pile of leaves (cm)

20° C 14.89 13.21 11.55 10.76

32° C 15.09 10.34 8.82 6.60

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Cycling of MatterMatter and Energy

4 Which of the following organisms is responsible for thedecomposition of organic matter in a forest?

A Insects

B Bacteria

C Bushes

D Rabbits

5 Which of the following describes an example of biomass decay in a habitat?

A Bacteria break down dead plants and add nutrients to the soil

B Mountain lions hunt and kill smaller mammals to get energy

C Plants use sunlight to produce glucose during photosynthesis

D Hot and cold temperatures weather and break down rocks

4

6 What type of energy is released as decomposition takes place in a compost bin?

A Light

B Nuclear

C Hydroelectric

D Thermal

Cycling of MatterMatter and Energy

7 Nitrogen from living organisms is returned to the atmosphere by the action of —

A autotrophs such as algae.

B consumers such as animals.

C decomposers such as bacteria.

D producers such as green plants.

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8 The graph shows the temperatures in a classroom compost bin for eight weeks. During which time period was the most decomposition occurring?

A During Week 1

B During Week 2

C During Week 3

D During Week 4

Cycling of MatterMatter and Energy

6

9 During decomposition, bacteria in the soil —

A change nitrogen into a useful form

B remove carbon from the atmosphere.

C cause weathering of rocks and minerals.

D produce sugars that animals can ingest.

Cycling of MatterMatter and Energy

10 Some students used the setup shown to model the cycling of water in a habitat. In the model, which part of a natural habitat is represented by the water droplets collecting on the bottom of the pan?

A Sun’s thermal energy drying up a lake

B Moisture given off by plants through leaves

C Rain, snow, and other forms of precipitation

D The formation of clouds in the atmosphere