Answer:
amount of gas(moles)
Explanation:
by the ideal gas equation, pV=nRT
when T kept constant,
no. of moles remains constant most of the cases unless gas is added into the container or removed.
pressure & volume can remain constant but not simultaneously.
if it's given that the container is rigid or an open system pressure remains constant.
hence out of the given choices, the most suitable answer is the amount of gas or moles
hope this helps ;) (please mark brainliest if possible, trying to rank up)
