NECO Biology 2025 Objective — Question 33

Question 33 of 50 from the National Examinations Council (NECO) Biology 2025 Objective paper, with the correct answer and a full explanation.

Which of the following sequences represents the trend in eutrophication?

A. Heavy mineralization -> lack of oxygen -> massive algal growth
B. Excessive nitrates -> massive algal growth -> lack of oxygen -> death of aquatic organismsCorrect
C. Excessive phosphates -> lack of oxygen -> massive algal growth -> death of aquatic organisms
D. Massive algal growth -> excessive nitrates -> lack of oxygen -> excessive nitrates

Explanation

Eutrophication follows the sequence: excess nutrients (like nitrates) enter the water, causing massive algal growth, which subsequently depletes oxygen, leading to the death of aquatic organisms.

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