Why different restriction enzymes make different dna fragments?

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.

Factors that can increase mutation rates a. high temps b. low temps c. food additives d. uv rays

What is the statement plant growth is affected by the color light