7. State the different types of bio-geo- chemical eyeles and explain the
importance of those cycles.

How do antiviral drugs work? in your own words.

Long term exposure to waves can cause sunburns and skin cancer.

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.