Question

Which of these human activities is a serious threat to marine ecosystems? A) Fishing in estuaries. B) Dumping wastes in landfills. C) Sinking chemical wastes in the ocean. D) Burning wastes rather than dumping them in landfills.

Answer 1

Sinking chemical wastes in the ocean is a serious threat, because the chemicals will poison all the living things around it. so the correct answer is C.
     Hope this helps !

Answer 2

C because burning waste does not affect the marine ecosystems