In what form does oxygen that supports marine life exist?

Oxygen that supports marine life primarily exists in a dissolved state in water. This dissolved oxygen is crucial for the survival of aquatic organisms, including fish, invertebrates, and microorganism. In this form, oxygen is available for organisms to breathe as they extract it from the water through gills or other respiratory systems.

While oxygen is present in the gaseous state as part of the atmosphere, it must be dissolved into water to be utilized by marine life. The solid state of oxygen is not relevant in the context of marine environments because it exists at extremely low temperatures, far below what is typically found in oceans or other bodies of water. Vapor state oxygen refers to water vapor, which is not directly usable by marine life for respiration. Therefore, the option that accurately reflects how oxygen supports marine life is its presence in a dissolved state.