Question 1

Which statement best describes the difference between energy flow and chemical cycling in ecosystems?

Accepted Answer

Energy flows in one direction, while chemicals are recycled between biotic and abiotic reservoirs.

Question 2

In the diagram shown, which component acts as the main reservoir for nutrients before they become available to producers?

Accepted Answer

Abiotic reservoirs

Question 3

Which of the following is an example of a geological process in a biogeochemical cycle?

Accepted Answer

Volcanic eruptions releasing minerals

Question 4

A farmer applies fertilizer to a field, increasing the amount of nitrogen in the soil. Which biogeochemical cycle is most directly affected by this action?

Accepted Answer

Nitrogen cycle

Question 5

Which process is responsible for converting atmospheric nitrogen ($$N_2) $$into a form usable by plants?

Accepted Answer

Nitrogen fixation

Question 6

If a lake receives excessive nutrients from agricultural runoff, what is the most likely ecological consequence?

Accepted Answer

Eutrophication leading to oxygen depletion and fish kills

Question 7

Which equation best represents the process of photosynthesis, a key part of the carbon cycle?

Accepted Answer

$$6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6$ + 6O_2$$

Question 8

Which human activity most directly increases the amount of sulfur dioxide ($$SO_2) in $$the atmosphere?

Accepted Answer

Burning fossil fuels such as coal and oil

Question 9

What is the primary role of decomposers in biogeochemical cycles?

Accepted Answer

They break down organic matter, returning nutrients to abiotic reservoirs.

Question 10

Which of the following best explains why phosphorus is often a limiting nutrient in aquatic ecosystems?

Accepted Answer

Phosphorus does not have a gaseous phase and is mainly found in rocks, making it less available.

Question 11

A power plant releases large amounts of $$SO_2$$ into the atmosphere. What environmental problem can this lead to?

Accepted Answer

Acid deposition (acid rain)

Question 12

Which process in the nitrogen cycle returns nitrogen to the atmosphere as $$N_2$$?

Accepted Answer

Denitrification

Question 13

Which of the following is a direct consequence of disrupting the water cycle by deforestation?

Accepted Answer

Decreased infiltration and increased runoff

Question 14

A lake is experiencing algal blooms due to excess phosphorus. What is the most likely source of this phosphorus?

Accepted Answer

Agricultural fertilizer runoff

Question 15

Which formula represents the process of cellular respiration, which releases carbon dioxide into the atmosphere?

Accepted Answer

$$C_6H_{12}O_6$ + 6O_2 \rightarrow 6CO_2 + 6H_2O$$

Question 16

Which of the following ecosystem services is provided by wetlands?

Accepted Answer

Buffering coastal populations from tidal waves and hurricanes

Question 17

Which process in the nitrogen cycle involves bacteria converting ammonia ($$NH_3) $$into nitrite ($$NO_2$$^-$$) and nitrate (NO_3$^-$$)?

Accepted Answer

Nitrification

Question 18

Why is sustainability important in managing natural resources?

Accepted Answer

It allows current needs to be met without compromising future generations.

Question 19

Which of the following best describes the role of abiotic reservoirs in biogeochemical cycles?

Accepted Answer

They store chemicals outside of living organisms, making them available for cycling.

Question 20

A scientist observes that after a forest is cleared, the nearby river experiences increased nutrient runoff and decreased species diversity. Which biogeochemical cycle is most likely disrupted?

Accepted Answer

Water cycle

Biogeochemical Cycles: Cycling of Matter in Ecosystems

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