Which of the following is the most likely impact of plastic and marine debris on coral ecosystems?
a. microplastics can be ingested by the corals and can smother the reefs.
b. debris can cause the temperature of the water near corals to increase
c. microplastics can increase the numbers of phytoplankton near the reef.
d. it can prevent marine mammals from finding appropriate mates near the reefs.

Option 'A' is correct.

Explanation:

Microplastic can be ingested by the corals and can smother the reefs.

It is the most likely impact of plastic and marine debris on coral ecosystems.

As the people is continuously throwing plastics in the river .

At last it goes into the ocean where coral reefs eat them which kill them.

Marine debris is also causing coral reefs killed like vessels which get lost  damaged the coral reef.

Debris may contained net which can break off pieces of coral that get tapped in it.

Hence , option 'A' is correct.

true is the answer : )