Rewrite the following sentence, using commas correctly. ​
I mailed the heavy, fragile package from the main, post, office.​

I mailed the heavy fragile package, from the main post office.

the main fragile post office,I mailed the heavy package.

is it multiple

the gas pressure p, gas volume v, and gas temperature t are given in the formula:   pv=nrt,

r is the gas constant, and n is the number of gas moles.

if the container is cooled and remains under atmospheric pressure, where r is a constant that does not change, the volume of the container remains the same, the conclusion is drawn that, with all other values ​​unchanged, the number of gas moles n, is decreases.

the right answer is a.