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Carbon and Nitrogen Cycles

Total questions: 13

Worksheet time: 39mins

Name
Class
Date
1.

Which of the following most completely describes the role of nitrogen-fixing bacteria in the nitrogen cycle? Nitrogen-fixing bacteria convert

a)

nitrates intro nitrogen gas

b)

ammonia into proteins

c)

molecular nitrogen gas into ammonia into nitrites and nitrates

d)

nitrites into nitrates

2.
Which of the following removes carbon from the atmosphere?
a)

Combustion

b)

Respiration

c)

Photosynthesis

d)

Death

3.
A gas produced by animals during respiration that plants use for photosynthesis.
a)
Oxygen
b)
Carbon Dioxide
c)
Photosynthesis
d)
Radiation
4.

What do legumes have on their roots?

a)

nodules full of nitrogen fixing bacteria

b)

nodules full of seeds

c)

nodules full of carbon dioxide

d)

nodules full of trace gases

5.

What process converts nitrogen gas into a biologically useful (fixed) form?

a)

Respiration

b)

Assimilation

c)

Denitrification

d)

Nitrogen fixation

6.

Which organisms play the largest role in converting nitrogen into various usable forms and back to a gas form?

a)

rabbits

b)

bacteria

c)

plants

d)

worms

7.

The process of breathing in oxygen and releasing carbon dioxide into the air (or water) is...

a)

Assimilation

b)

Decomposition

c)

Photosynthesis

d)

Respiration

8.

Which of the following does NOT release carbon dioxide into the atmosphere?

a)

volcanic activity

b)

respiration

c)

photosynthesis

d)

fossil fuel combustion

9.
Plants and animals need nitrogen to make __________.
a)
Protein
b)
Carbohydrates
c)
Lipids
d)
Nucleic Acids
10.
Which cycle is this?
a)

Carbon

b)

Nitrogen

c)

Phosphorus

d)

Water

11.
Which cycle is this?
a)

Carbon

b)

Nitrogen

c)

Phosphorus

d)

Water

12.
Which of the following add carbon dioxide to the atmosphere?
a)
volcanoes
b)
combustion of fossil fuels
c)
animal and plant respiration
d)
all of these
13.
What is happening at 1?
a)
respiration: releasing CO2
b)
decomposing CO2 in the soil
c)
photosynthesis: absorbing CO2
d)
turning CO2 from the atmosphere into organic molecules