What is the term given to those organisms living in the pelagic zone that can swim? question 4 options: nekton benthos coral reef plankton save?

Hello! 

The term given to those organisms living in the pelagic zone that can swim is Nekton

The Pelagic zone is also called the open ocean. It's the water column that is not over the continental shelf. The living organisms in the pelagic zone that can swim are called Nekton. This is a term given by Ernst Haeckel, a German biologist, to distinguish the active organisms (Nekton) from the passive ones (Plankton). 

Organisms that can be classified as Nekton include Sharks, Squids or Crabs, among many others. 

The answer would be sand and gravel