Enzymes are able to speed up chemical reactions because they- a) increase the temp inside the cell
b) reduce the friction between the reactants
c) make the raw materials more chemically reactive
d) lower the activation energyof the reaction

i think that is new experiments yield untrustworthy data and should be carefully considered, because you don't know what will happen with the experiments.

some inherited genetic mutations can be good for the offspring, so the answer is different genetic mutations cause many forms of cancer.