Which statement best describes why a chemical change is different from a physical change? a chemical change results in a different state of matter, and a physical change results in a new substance being formed. a chemical change is used by scientists to create new substances, and a physical change happens naturally. a chemical change results in a new substance being formed; whereas, a physical change will result in a different state of matter. a chemical change is used to identify characteristics of a substance, and a physical change identifies the behavior of a substance when in a reaction.

What adaptation is apparent in the bodies of the three tortoise species shown in figure 16-2

Explain why in any given geographical region, women tend to have lighter skins( by 3-4% on average) than men?

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