Questions: RALC CR Biology B The Cycles of Matter Pre-Test Active 1 2 3 4 5 6 7 8 9 10 time remaining 58:34 Which of the following would be a result of eutrophication of a lake? undergrowth of water plants hypoxia, or low levels of oxygen decreased decomposition inactivity of fertilizers Save and Exit Next Submit Mark this and return

The answer is the second one: hypoxia, or low levels of oxygen.

Explanation for each option:

• Undergrowth of water plants: This is incorrect. Eutrophication typically leads to an overgrowth of water plants and algae due to the increased availability of nutrients like nitrogen and phosphorus.

• Hypoxia, or low levels of oxygen: This is correct. Eutrophication often results in hypoxia because the overgrowth of algae eventually dies and decomposes, consuming oxygen in the process and leading to low oxygen levels in the water.

• Decreased decomposition: This is incorrect. Decomposition actually increases during eutrophication as the excess plant material and algae die and are broken down by bacteria, which consume oxygen in the process.

• Inactivity of fertilizers: This is incorrect. Fertilizers are typically the cause of eutrophication, as they introduce excess nutrients into the water, promoting the overgrowth of algae and aquatic plants.

In summary, eutrophication of a lake primarily results in hypoxia due to the increased decomposition of organic matter, which depletes oxygen levels in the water.