Which ocean zone is known as the open ocean?

The pelagic zone is known as the open ocean because it encompasses all of the water column in the ocean that is not associated with the coastal or benthic areas. This zone is characterized by its depth and distance from shore, where the water is typically deep and includes both the neritic zone (near the coast) and the oceanic zone (deep ocean). The pelagic zone is crucial for many marine organisms, including fish and plankton, which thrive in these vast water areas that are not influenced by land or fixed structures.

The benthic zone, in contrast, refers to the ocean floor and the associated sediments, which includes organisms that live on or in the seafloor rather than in the water column itself. The photic zone is the upper layer of the ocean where sunlight penetrates, allowing photosynthesis, but it is only a part of the pelagic zone. The littoral zone is the coastal region of the ocean, close to shore, featuring a distinct habitat where land and water meet. Therefore, the pelagic zone represents the expansive, open waters of the ocean, making it the correct answer.