Which of the following is an example of how enzymes are catalyst? A. Enzymes can alter the free energy change (∆G) for a chemical reaction.

B. Enzymes increase the free energy of the reactants to make the reaction go faster.

C. Enzymes provide the activation energy for the reactions they facilitate.

D. Enzymes lower the activation energy so that reactants absorb enough energy to reach transition state.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Ecology can best be described as the study of what

Located at the epidermal-dermal junction of the skin. select all true statements about the transformation of melanocytes into abnormal cell