Answer: moles
Explanation: Boyle's law:
Boyle's law stated that volume and pressure are inversely proportional to each others by keeping the number of moles and temperature constant.
Mathematical expression:
P₁V₁ = P₂V₂ (n and T are constant)
Charles's law:
Charles's law stated that temperature and volume are directly related related to each others by keeping number of moles and pressure constant.
Mathematical expression:
V₁/T₁ = V₂ /T₂ (n and P are constant)
Gay-Lussac's law:
This law stated that pressure of gas is directly related to its temperature by keeping the number of moles and volume constant.
Mathematical expression:
P₁/T₁ = P₂ /T₂ (n and V are constant)