The basic unit of structure and function is cells
Explanation: Animal social behavior, the suite of interactions that occur between two or more individual animals, usually of the same species, when they form simple aggregations, cooperate in sexual or parental behavior, engage in disputes over territory and access to mates, or simply communicate across space.
The answer is D, white blood cells.
The main function of white blood cells is to defense the body from bacteria or other pathogens. There's 2 main kinds of white blood cells, lymphocytes and phagocytes. Lymphocytes mainly produce antibodies that can kill bacteria or any pathogens, and phagocytes can ingest the pathogens directly.
Therefore, since the white blood cells can protect our body, they're part of our immune system.
The blood get it's greatest pressure from the heart. The heart pumps the blood out.
a population of mealworms because they do not need water at all
