Answer:its a covalent bond
Explanation:
C. all systems work together to maintain homeostasis.
an organism is a collection of Organ systems each of which must work in unison for proper function.
Answer:
Humoral immunity:
Humoral immunity is mediated by the macromolecules present in the extracellular fluid. This immunity provides protection against the pathogens present in the extracellular fluid. B- cells are mainly produced by the humoral immunity. The plasma cell and memory cells are generated in the human body. Antibodies kill the pathogens in humoral immunity.
Cell mediated immunity:
Cell mediated immunity is activated by the infected cells. This immunity provides protection against intracellular pathogens. T- cells are mainly produced by cell mediated immunity. T helper cells and T killer cells are mainly produced in the cell mediated immunity. Cytokines kill the pathogens in case of cell mediated immunity.
They have all of the above. All living things need an endocrine, circulatory and digestive system to live.
