Yes A is the correct answer
<span>there is more than one path for the electrons to take.</span>
<span>DNA is made of chemical building blocks called nucleotides. These building blocks are made of three parts: a phosphate group, a sugar group and one of four types of nitrogen bases. To form a strand of DNA, nucleotides are linked into chains, with the phosphate and sugar groups alternating.</span>
Variations are beneficial for the survival of the species. Populations of organisms fill well-defined places, or niches, in the ecosystem, using their ability to reproduce.However, if some variations were to be present in a few individuals in these populations, there would be some chance for them to survive.
