The Study of organisms inhabiting the sea and Ocean and the physical and chemical characteristics of their environment is:

B. Marine Biology

Marine Biology is the study of organisms inhabiting the sea and ocean and the physical and chemical characteristics of their environment. This field encompasses a wide range of topics, including the evolution, behavior, and ecology of marine organisms, the role of marine ecosystems in the biosphere, and the impacts of human activities on the marine environment. Marine biologists may study a wide range of organisms, from tiny plankton to massive whales, and work to understand their relationships with each other and with their environment.

A. Social Biology is not a recognized field in biology.

C. Environmental Biology is the study of the relationship between living organisms and their environment, including the effects of human activities on the natural world.

D. Freshwater Biology is the study of freshwater ecosystems and the organisms that inhabit them, including rivers, lakes, and wetlands.