What system tells the muscular system which muscles to contract and when to contract

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.

The color of the fur is the genotypephenotype.the genetic combination of alleles that determine the fur color is called the genotypephenotype.

Slow down transpiration by the stomata question 9 options: a guard cells; closing b chloroplasts; closing c guard cells; opening d chloroplasts; opening