Why are there more people with sickle cell disease in one part of the world than in other parts?

Why is excretion necessary to maintain homeostasis?

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.

Where can dna be found in a prokaryotic cell