Identify and describe layer A in the figure above

What is the next step in the process after a substrate enters the active site of an enzyme

Which short-term environmental changes would a very small asteroid or comet impact on earth most likely cause? check all that apply. flooding extinction craters on surface changes in weather patterns death of organisms and populations

During crossing-over, a. genetic material is exchanged between nonsister chromatids, resulting in new combinations of alleles. b. nonsister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. c. one homologous chromosome of a tetrad is exchanged with another tetrad, resulting in new combinations of alleles. d. sister chromatids from each homologous chromosome of a tetrad are exchanged, resulting in new combinations of alleles. e. genetic material is exchanged between sister chromatids, resulting in new combinations of alleles.