What does it mean when scientists say that living organisms share a universal genetic code 2. how does a universal genetic code relate to the hypotheses about the origin of life on earth? 3. how are self-replicating molecules, such as rna molecules in the "rna world" hypothesis, essential to the most popular hypotheses about the origin of life on earth? 4. how might similarities and differences in genetic codes, or the proteins built as a result of these codes, be used to determine how closely related different species are? 5. based on the amino acid sequence data for the cytochome-c protein, chimpanzees and humans share an identical coding sequence. what other species identified on the chart has a coding sequence that is most closely related to the humans and chimpanzees and most distantly related? explain your answer?

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

To determine if a particular plant is homozygous or heterozygous, you would have to test cross with a

The scales shown in the introduction measure mass, or the amount of matter in a particular object. the scientific law of conservation of mass states that matter cannot be created or destroyed during a chemical reaction, but it can change from one form to another. did the simulation support this scientific law? explain why or why not.