During normal breathing the volume of air we exchange is about

The volume is 500ml and it is called tidal volume.

Breathing can be defined as the process in which air moves into the lungs either from the nose or mouth called inspiration and moves out of the lungs during expiration. Thus, the free flow of air from the mouth or nose to the lungs and back to mouth or nose is very important to the survival of living organisms. However, in normal breathing the volume of air that moves into the lungs through mouth or nose in normal breathing is 500ml and it is called tidal volume.

answer///multiple alleles;

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.