Answer:
This is the basis for Chargaff's rule; because of their complementarity, there is as much adenine as thymine in a DNA molecule and as much guanine as cytosine. Adenine and thymine are connected by two hydrogen bonds, and cytosine and guanine are connected by three hydrogen bonds
1:D
2:A
3:D
4:B
5:D
.................................................................
The anwser is BBBBBBBbbbbbbbbbb
Reflections and absorption by the atmosphere prevent some radiation from reaching Earth's surface.
A change in or the process of changing, e.g. nature, form or quality.
Mutations are caused<span><span>DNA fails to copy accurately
Most of the mutations that we think matter to evolution are "naturally-occurring." For example, when a cell divides, it makes a copy of its DNA — and sometimes the copy is not quite perfect. That small difference from the original DNA sequence is a mutation.<span>
</span></span><span>External influences can create mutations
Mutations can also be caused by exposure to specific chemicals or radiation. These agents cause the DNA to break down. This is not necessarily unnatural — even in the most isolated and pristine environments, DNA breaks down. Nevertheless, when the cell repairs the DNA, it might not do a perfect job of the repair. So the cell would end up with DNA slightly different than the original DNA and hence, a mutation. hope that helped
</span></span>
