Answer:
This is a slightly vague question because there are many reasons why DNA can be damaged and determining which organelle was at fault is generally a case by case matter. but the only part of a cell that you could considered to be tasked with protecting genetic material is the nuclear envelope which is simply a phospholipid bilayer surrounding the nucleus and/or the nucleolus so I would say the answer is the nuclear membrane and/or nuclear envelope.
<span>I believe you are looking for the term, Dichotomous Keying.</span>
The thickest layer is the mantle, while the crust is the thinnest layer.
