Process requiring energy for the movement of particles across a cell membrane against the concentration gradient.

Ascientist is studying muscle twitches in chicken quadriceps. to activate the muscle, he needs to provide stimulus to the

Which of the following occurs most often in a population when genetic variation and overproduction are present? some organisms have a lower reproductive success than others. some organisms have a higher reproductive success than others. some organisms have no reproductive success. some organisms do not have genetic variation.

25. what does meiosis create? haploids or diploid? somatic cells or gametes?