During prophase, the parent cell chromosomes — which were duplicated during S phase — condense and become thousands of times more compact than they were during interphase. ... Cohesin forms rings that hold the sister chromatids together, whereas condensin forms rings that coil the chromosomes into highly compact forms.
I believe the answer is comparative anatomy. It is the study of the similarities and differences in the structures of different species. Similar body parts may be homologies or analogies, such that both provide evidence of evolution. Similarities in embryos are evidence of common ancestry. For example all vertebrates embryos have gill slits and tails.
<span>Any type of pharmaceutical product or dietary supplement must be tested in clinical trials before they can be marketed in order to assess their safety for the general public's consumption and to confirm their intended purpose. While not a complete fail safe, these tests intend to prove a reasonable sense of safety for the product.</span>
Answer: By us people breathing in oxygen and breathing out carbon dioxide.