HELP PLEASE: how can synthetic fertilizers affect the stability of photic zones in lakes and open oceans?

Sarah and john are having a discussion on genetic diversity. sarah believes that it happen over a long period of time. john it happens immediately. who is correct? a. sarah is correct because genetic diversity occurs over a long period of time. b. john is correct because genetic diversity occurs immediately. c. both are correct because genetic variation can occur or long period of time. d. neither are correct because genetic diversity occurs over any period of time

What is the identity of the planets?

How have crops been modified? a.plants have been made more susceptible to pests b.plants have been made resistant to herbicides c.plants have been made more susceptible to herbicides d.plants have been modified to have reduced yield