What is true of experimental designs that are used in scientific research?

Explain the side effects of cancer treatments

Human genes only differ by less than percent. a. 1 b. 6 c. 11 d. 16

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled