PLEASE HELP -Under what conditions will water enter a cell?

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

How energy flows through each level in this energy pyramid. is all the matter and energy from one level transferred to the next level?

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.