DNA replication begins when something called Helicase (an enzyme) unwinds the helix structure of the DNA. It does this so that Primase can then come along and set down an RNA primer.
I think it might be C I am not 100% sure though
Answer:
<h2><u>
A. Having a nucleus</u></h2>
Explanation:
Many organisms have nuclei, but certain types of one-celled prokaryotes and bacteria do not have one.
The phenotype is just a characteristic/trait.
For instance Brown and Green are phenotypes of eye color.
This can also be used in Punnet Squares, and could be displayed as B and G.
B equaling dominant Brown, and G = dominant Green, vice versa to g and b where they are recessive.
I think the correct answer from the choices listed above is option A. It is the alveoli that is composed of single layer <span>surrounded by a network of capillaries. These are used to allow oxygen and carbon dioxide to move from the lungs to the bloodstream.</span>