Question

The increased nitrogen in rivers and lakes boosts the growth of ....... and other phytoplankton at the cost of other aquatic organisms.

Answer 1

Eutrophication: Phosphorus and nitrates dissolved in water act as nutrients and accelerate the growth of algae that may form a mat on the water surface. This increased productivity is called eutrophication, The algae use oxygen at night and may deoxygenate the water enough to kill the fish and other animals.

So, the correct answer is 'algae'.