Why did scientists think the world was experiencing global cooling between the 1940’s and 1970’s.
a. pollution was blocking sunlight. b. pollution was trapping heat in the atmosphere. c. winters were the longest and coldest since the last ice age. d. biodiversity was declining.

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

All phases of matter may have a fixed mass

Produce proteins by following coded instructions that come from the nucleus of the cell.