Question

marine snow is _________.
a. pieces of organic matter that were once part of living organisms
b. a mixture of living plankton
c. snow from land that has entered aquatic ecosystems
d. large salt crystals that have not dissolved in ocean water

Explanation:

Marine snow consists of organic matter that was once part of living organisms. It is not living plankton (b), not land - derived snow (c), and not large salt crystals (d).

Answer:

A. pieces of organic matter that were once part of living organisms