Question

8 nutrients circulate endlessly throughout the environment in complex cycles called
a eutrophication cycles.
b respiration cycles.
c photosynthesis cycles.
d biogeochemical cycles.
9 a carbon sink is defined as a place that:
a releases more carbon than it absorbs.
b absorbs more carbon than it releases.
c stores carbon for a short period.
d. is composed only of inorganic carbon.
10 how does deforestation primarily contribute to the increase of carbon dioxide in
the atmosphere?
a. the decomposing wood quickly releases all of its carbon.
b. fewer plants are available to perform photosynthesis, removing carbon.
c. the soil loses its ability to absorb carbon.
d. the process of logging uses up atmospheric oxygen.
11 the formation of fossil fuels from dead organisms under heat and pressure is an
example of carbon storage in the:
a. atmosphere
b. hydrosphere
c. sediments/geosphere
d. biosphere
12 during the process of nitrogen fixation, nitrogen gas is converted to
a. water.
b. phosphorus.
c. ammonia.
d. carbon dioxide.
13 the phosphorus cycle involves mainly the
a. atmosphere and biosphere.
b. hydrosphere and atmosphere.
c. geosphere and biosphere.
d. biosphere and hydrosphere.
14 eutrophication (also known as dead zones) is often caused by the addition of
a. carbon and/or proteins.
b. lipids and/or hydrocarbons.
c. carbon and/or phosphorus.
d. phosphorus and/or nitrogen.

Explanation:

• Question 8: Nutrients circulate in biogeochemical cycles. Eutrophication is a water - quality issue, respiration is part of the carbon cycle but not the overall nutrient cycle name, and photosynthesis is a process in the carbon cycle.
• Question 9: A carbon sink absorbs more carbon than it releases. If it released more (A), it would be a source. Short - term storage (C) is not the definition of a sink. And being only inorganic (D) is incorrect as carbon sinks can involve organic matter (e.g., forests).
• Question 10: Deforestation means fewer plants for photosynthesis (which removes carbon dioxide). Decomposing wood (A) doesn't release all carbon quickly. Soil (C) is not the main factor here. Logging (D) is not the primary way deforestation affects carbon dioxide (photosynthesis reduction is).
• Question 11: Fossil fuels form in sediments/geosphere. The atmosphere (A) has gaseous carbon, hydrosphere (B) has dissolved carbon, and biosphere (D) has living organisms' carbon.
• Question 12: In nitrogen fixation, nitrogen gas (\(N_2\)) is converted to ammonia (\(NH_3\)). It's not converted to water (A), phosphorus (B), or carbon dioxide (D).
• Question 13: The phosphorus cycle mainly involves the geosphere (rocks as a source) and biosphere (organisms using phosphorus). Phosphorus is not a major gas in the atmosphere, so options with atmosphere (A, B) are wrong. And it's not mainly in the hydrosphere in terms of its cycle compared to geosphere - biosphere interaction.
• Question 14: Eutrophication is often caused by phosphorus and/or nitrogen (from fertilizers etc.). Carbon (A, C) is not the main cause. Lipids and hydrocarbons (B) are not the typical nutrients causing eutrophication.

Answer:

1. D. biogeochemical cycles.
2. B. Absorbs more carbon than it releases.
3. B. Fewer plants are available to perform photosynthesis, removing carbon.
4. C. Sediments/Geosphere.
5. C. ammonia.
6. C. geosphere and biosphere.
7. D. phosphorus and/or nitrogen.