How is a scientific theory developed? a) an experiment is repeated over and over again with the same results. b) many different experiments are repeated many different times. c) a single experiment is carefully performed once. d) one scientist supports his or her hypothesis with an experiment.

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms

ionic bonds are two oppositely charged ions that attract. a sodium ion has a 1 positive charge; a chloride ion has a 1 negative charge. sodium and chloride have oppostive charged ions that attract which forms an ionic bond. a chemical bond formed when two atoms share electrons is called