Which of the following is not true about polar bears?
a. they all hibernate.
b. they have black skin that them absorb heat.
c. their fur is transparent and hollow and trap heat.
d. they have oversized paws with rough pads that them walk on snow and ice.

Which statement describes a way in which the digestive and excretory systems work together? a. the nephrons absorb nutrients from food going to the large intestine. b. the excretory system balances blood gases in the small intestine. c. the intestinal villi filter blood and send wastes to the bladder. d. the excretory system balances the salts and water obtained from digested food