Factors that can alter the level of expression of a gene include

These could be environmental factors such as;

Exposure to UV radiation that causes mutations

an increase in salinity.

an increase in environmental temperature.

presence of a particular energy substrate.

Gene expression can be affected in different stages from transcription, RNA processing, to post-translation modification.

clumped distribution, because you'de have all of the population gathered in a relatively small are.

it's the most common because it provides protection and a mate for reproduction

example: humans, seeweed, cattles, etc.

the answer is c. it will give up it's valence electron to the other atom.