Maximizing the surface area is the best use by which of the body systems?

-Digestive
-Skeletal
-Skin
-Muscular

The is a thin membrane that transmits sound waves into the middle ear.

Aperson who doesn't have enough calcium in his or her diet is at risk for developing bones that are weak and break easily. this condition is known as  a.  osteoporosis.    b.  crohn's disease.    c.  celiac disease.    d.  hemophilia.

Which principle described by psychologist martin seligman fosters an overall positive attitude by using thinking and behavior techniques to resist negativity?