Which equation has water as a product in the chemical reaction?
a. na + cl nacl
b. h2o h2 + o2
c. naoh + h2 na + h2o
d. co2 + o2 + energy c6h12o6 + o2

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.