Truel false Theories can change over time as new evidence is discovered.

Which phrase best describes surface currents? 1. up-and-down ocean movement caused by wind 2. waves that hit the shore at an angle and transport sand 3. streams of warm water flowing through the ocean and caused by wind 4. waves that approach the shore and cause their crests to fall into their troughs

Creation of an unnaturally uniform sample to represent a diverse populationcan be avoided by: a. including only willing b. asking another scientist for .c. choosing only identical participants. d. selecting individuals at random.

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