Can you answer this science question for me please?

Explain why the plants cortex would serve as the best food source for animals

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

Genetic disorders can result when sister chromatids fail to seperate properly. during what phase is this problem most likely to occur?