Natural selection that favors the one extreme in the range of variation for a phenotype is called:
disruptive selection
directional selection
stabilizing selction
none of these

Identify the various levels of atmosphere. troposphere mesosphere exosphere stratosphere thermosphere

The pharynx is the structure in the body that serves as a pathway of both air and food. how does the body make sure that food does not get into the lungs? the salivary glands secrete enzymes that pull food out of the air pathway. the small intestine pushes the air out of the digestive system. the pancreas breaks down food in the air pathway. the epiglottis closes the air pathway so that food will not enter it.

When you run, you begin to breathe heavier and faster. your heart beats more quickly, bringing more oxygen to your cells. which organ systems are working together here?