A testable idea that attempts to explain a phenomenon or answer a scientific question is the definition of a what ?

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

Which of the following does not make up ground substance of connective tissue? hyaluronic acid elastic fibers glycosaminoglycan proteoglycan

Which describes the changes in the earths motion?