Cell membrane, Organells, flagella
<span>helicase<span>DNA helicase is the enzyme that unwinds the DNA double helix by breaking the hydrogen bonds down the center of the strand. It begins at a site called the origin of replication, and it creates a replication fork by separating the two sides of the parental DNA.<em /></span></span>
It requires energy when a substance must travel against a concentration gradient through the membrane
Answer:
A great example is the peppered moths evolution. Since the Industrial Revolution the birch trees started to turn black from the soot. This casued all the white moths to be eaten from birds. The ones that were left to mate were black moths which favored the black gene. So overtime black moths became more common. They were naturaly selected based on color to survived and pass down their black colored genes.
Explanation:
<span>Without variation, there is no difference between members of a population to be "selected for" in the first place. This is a basic tenet of natural selection. A new trait must arise in order to advance or decrease the fitness of the individual, and hence, its ability to pass on its genes.</span>
