Question

the pelagic zone is best defined as which of the following?
the intertidal zone only
all the open water of the ocean
the benthic zone only
the deep ocean

Explanation:

The pelagic zone refers to the open - water area of the ocean. The intertidal zone is the area between high and low tide. The benthic zone is the ocean floor. The deep ocean is a part of the pelagic zone but not the entire definition.

Answer:

all the open water of the ocean