Answer:
Getting clean air to breathe and clean water is a necessity to human beings, whereas having personal freedom is not.
They are saying that you should chose brand x over the other brands
Because it makes it easier for the person who is interested in hiring you to read, and you'll more likely be hired with a neat understandable letter.
Commas are used when two independent clauses are joined with coordinating conjunctions (For, And, Nor, But, Or, Yet, So).
Example: I wanted to play cricket, but I was not feeling well.
However, there are always exceptions to this.
Hope this helps:)
