What unit of measurement would I use to measure the thickness of a hair?

mass and weight are closely related because mass affects the weight of an object experiencing the effects of gravity. weight is the measure of the force of gravity on an objects's mass, while mass is the measure of how much matter there is in an object.

barometer is an instrument used to measure the atmosphere's pressure. the high air pressure relative to average levels is associated with calm and sunny weather. on the other hand, low pressure is associated with bad weather, high winds, and rain. 

during expiration the diaphragm relaxes, which causes the diaphragm to move downwards. the contraction of diaphragm increases the space for expansion of lungs. hence, the diaphragm relaxes and positioned downward during expiration.