B. Healthier ecosystems. If you're talking about benefits, this is the only positive on this list. The others are listing the difficulties or downsides.
Answer:
B. NADH
Explanation:
For one cycle, two molecules of carbon, three molecules of NADH, one molecule of FADH2 and one molecule of ATP or GTP are produced.
An algal bloom affects the whole ecosystem. Consequences range from the benign feeding of higher trophic levels, to more harmful effects like blocking sunlight from reaching other organisms, causing a depletion of oxygen levels in the water, and, depending on the organism, secreting toxins into the water.