Most of the oxygen in the atmosphere is made by algae. Where do most of the algae live? coastal ocean
deep ocean
ponds
lakes

Coastal Ocean!

Explanation: It’s important to remember that although the ocean produces at least 50 percent of the oxygen on Earth, roughly the same amount is consumed by marine life. Like animals on land, marine animals use oxygen to breathe, and both plants and animals use oxygen for cellular respiration. Oxygen is also consumed when dead plants and animals decay in the ocean.

This is particularly problematic when algal blooms die and the decomposition process uses oxygen faster than it can be replenished. This can create areas of extremely low oxygen concentrations, or hypoxia. These areas are often called dead zones, because the oxygen levels are too low to support most marine life.

NOAA’s National Centers for Coastal Ocean Science conducts extensive research and forecasting on algal blooms and hypoxia to lessen the harm done to the ocean ecosystem and human environment.

Ais the correct answer