Describe the main principles of natural selection: 1)Populations evolve, individuals do not
2)Variations occur naturally within a population
3)All species have a capacity to overproduce
4)Adaptations help individuals compete successfully for survival
5)Beneficial adaptations will become more common in a population
6)Species can evolve into new species over many generations of successful adaptations

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

Control of the body is accomplished by which of the following body systems? nervous system and circulatory system endocrine and repertory system circulatory and respiratory systems nervous system and endocrine systems

Which statement best describes a typical difference that could be found between the "analysis" and "conclusion" sections of a lab report? a) only the "conclusion" describes errors that occurred during the experiment, and only the "analysis" section suggests further research.b) only the "analysis" section includes specific data comparisons, and only the "conclusion" section suggests further research.c) only the "analysis" section discusses whether the original hypothesis was supported, and both sections include graphs of data.d) only the "conclusion section discusses whether the original hypothesis was supported, and both sections suggest further research.(the answer is b i just took the test)