Question

multiple - choice question
using too much fertilizer can add too much nitrogen to aquatic ecosystems. this can cause an algal bloom which
makes the ecosystem healthier and able to support more life
blocks sunlight and starves things of oxygen
provides lots of food for fish and birds

Explanation:

When there is an algal bloom due to excessive nitrogen (from over - use of fertilizers), the algae grow rapidly. They form a thick layer on the water's surface. This layer blocks sunlight from reaching the plants and other organisms below the surface. As a result, plants (which need sunlight for photosynthesis) cannot produce oxygen. Also, when the algae die, decomposers break them down. Decomposers consume a large amount of oxygen during decomposition. So, it blocks sunlight and starves things of oxygen.

Answer:

blocks sunlight and starves things of oxygen