Please help with the reasons for the adaptation. I don't understand :/

What would be the result if crossing over did not happen during meiosis in humans? a. there would be less genetic variation in humans. b. parents would be more likely to look like their children. c. the human population could not reproduce. d. children would have more chromosomes.

People with one sickle cell allele are not likely to get malaria. what is this an example of?

When rutherford performed his metal foil experiment, he was surprised that most of the alpha particles