It’s critical because it checks the cell for problems or mutations that could potentially harm it in later steps or make it like burst lol
Not to be too picky, but the question ought to say a positively charge ion rather than atom.
I will assume that is what you mean. An ion, using ordinary means, will be positive if it loses electrons (which are negative).
An ion can never gain protons. Left alone, the nucleus will remain unchanged for the rest of eternity. D is wrong.
C is wrong. If electrons are gained, the ion will go negative.
B is wrong for the same reason D is. An ion can't gain protons and it can't lose them.
A is the answer.
Nut is to shell as pea is to pod
The answer to the 3rd question is that chromosomes are tightly coiled bundles of DNA and carry many genes. For the 4th question, asexual reproduction can occur by binary fission and creates exact genetic copies of a parent.