What encompasses all forms of plant and animal life that live in water?

Aquatic life encompasses all forms of plant and animal life that inhabit water bodies, including oceans, rivers, lakes, and wetlands. This term is broad and inclusive, covering a wide range of organisms, from microscopic plankton to large marine mammals, as well as aquatic plants. This definition allows for the consideration of life in both freshwater and saltwater environments, emphasizing the diversity of species that thrive in various aquatic ecosystems.

The other options focus on specific aspects of aquatic organisms. For instance, marine biology is the study of organisms specifically in marine environments, which does not cover freshwater organisms. Hydrobiota refers specifically to the organisms that live in water but is a less commonly used term compared to aquatic life. Freshwater organisms specifically refer to life forms found in freshwater ecosystems, not accounting for those in marine environments, which are also part of aquatic life. Hence, the term aquatic life is the most comprehensive and accurate in describing all forms of plant and animal life in water.