What conditions are necessary for natural selection to occur

After fertilization, which type of cellular division is responsible for the growth and development of a complex, multicellular organism?

Producing disposable grocery bags consumes resources. recycling disposable bags is a solution that can recover some of the resources used to make new bags. which of the following behaviors could further refine the solution? a. disposing of bags by burning them b. reusing bags whenever possible c. using bags at once so that they do not break d. using only nonrenewable materials to make new bags subject is environmental science for apex users

If a human has 23 pairs of chromosomes in every muscle cell of its body how many chromosomes will be in a human egg or sperm