What might happen to the human heart during a trip to mars?
a. stop working completely
b. become too weak to pump blood
c. expand and become too large to work properly

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time

Which statement about the pancreas is not true? a. it is an endocrine organ in the abdomen. b. it release chemicals into the digestive system. c. it releases insulin to increase glucose levels. d. it release hormones into the bloodstream.

Long term exposure to waves can cause sunburns and skin cancer.