There is a multitude of evidence that supports how life has changed over time due to variation in the gene pool of different species. Which of the following choices below represents a scientific theory that explains these changes? * A. As environments and ecosystems change over time, those that acquire suitable traits are more likely to survive and reproduce and the gene pool changes because organisms must adapt to survive and reproduce.
B. As environments and ecosystems change over time, those with variations for traits that are more successful in the new conditions are more likely to survive and reproduce, thus changing the allele frequency in the gene pool.
C. Because the environments and ecosystems show little change over time, organisms are already adapted for surviving in their given habitats for which they are made.
D. Because the environments and ecosystem show little change of time, the organisms that choose to adapt to different environments will migrate and become suited for new habitats.

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. chytridiomycosis is a fungal disease first identified in 1998 as a cause of massive amphibian deaths. in some severely impacted populations, a few individuals have survived, perhaps because of some natural resistance. if these resistant individuals continue to survive and prosper, new resistant populations might emerge. this would be an example of the founder effect artificial selection genetic drift natural selection sexual selection

Prior to the development of dna fingerprinting, blood type could be used to determine possible parentage. although it might prove someone was not a parent, it could not show if someone was positively the parent, only that he or she might be a parent. which of the following is a true statement that can be made about parentage based on blood typing?

The earths core is made up mainly of what 2 substances? 2. like an egg, earth has a core, a layer surrounding the core, and a thin, hard outer layer. which layers of the earth match the layers of an egg?