8. a stroke is a sudden loss of brain function. it results from a lack of gas exchange with brain tissue, which occurs when the supply of blood to the brain is blocked. a stroke most likely results because of a problem in the system.

Next pretest: evolution select the correct answer in a laboratory population of flies, the female flies are gray and the males are yellowish gray. biologists observed that all the male flies had an equal chance for reproduction, but the male flies with the brightest colors were more likely to successfully reproduce. what phenomenon could explain such a change? a sexual selection b. disruptive selection c. stabilizing selection d. directional selection

According to your text, should be in the native language of the parents or guardians whenever possible. a. an email b. consent forms c. oral approval d. storybooks loaned out

According to the cell theory, which describes cells? a. all organisms are composed of multiple cells. b. all cells have the same structure and function. c. cells are found in everything on earth. d. living organisms are not created spontaneously