The independent variable is the only factor that a scientist varies for different groups in an experiment.
measures in an experiment.
keeps constant for each group in an experiment.
records throughout an experiment.

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

In a classic experiment using pea shape, mendel conducted two separate genetic crosses. in the first cross the parent plants were “true breeding” for pea shape; one had round peas ( r )and the other had wrinkled (r). the first cross produced a filial 1 generation of all round peas. in the second cross, mendel bred plants from the filial 1 generation. this cross produced different results. out of approximately 1000 plants, about 75% were round and 25% were wrinkled.

Which of the following describes a boom period? a. as one population increases, another population decreases. b. as one population increases, the other population also increases. c. as one population decreases, another population increases. d. as one population decreases, another population also decreases