A botanist who was studying a new plant ground up some of the leaf cells, then centrifuged the mixture. The organelles became fractionated such that the heavier fractions could produce ATP in the light, and the organelles in the light fraction could produce ATP in the dark. What do the fractions most likely contain? a. The lighter fractions contained more mitochondria.

b. The heavier fractions contained more peroxisomes.

c. The fractions contained more centrioles.

d. The lighter fractions contained more chloroplasts.

Read the following scenario to answer the following question. over the past 60 years, many amphibian species have experienced significant population declines, and some species have become extinct. scientists suspected that local human activities such as the destruction of wetlands, regional pollution, and deforestation were the main reasons for these losses. however, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks. these global declines suggest widespread problems including increased ultraviolet radiation, acid rain, and disease. in switzerland, for example, 14 of the 20 native amphibian species are threatened with extinction. when most populations of a wide-ranging amphibian species are lost and the few remaining populations are widely separated, we expect to see that a. the founder effect becomes increasingly important b. microevolution no longer occurs c. gene flow between populations is reduced d. artificial selection becomes a greater factor in microevolution

Explain why the plants cortex would serve as the best food source for animals

Types of scientific inquiry that biologist engage in that cannot be completely controlled