the degree of pathogenicity

an microscopic infectious agent that requires the cells of a host animal (or plant) in which to reproduce

nerve fibres that carry impulses from the central nervous system to an organ

thin layer of epithelial tissue covering all the organs in the peritoneal cavity

nerve fibres that carry impulses from an organ to the central nervous system

any of the body systems made up of internal organs, e.g. digestive and respiratory systems

volume of air that can be exhaled after the deepest possible inspiration; it is the usable air in the respiratory system

a number of unrelated organic compounds essential in small amounts for normal metabolism