What product or ratio of properties remains constant (PxT, TxV, P/V, V/T, etx)?When you have decided, label the "constant?" column with proper term and fill in the values.

In this phenomenon we talk about ideal gases, that is why in these equations the constant is the number of moles and the constant R, which has a value of 0.082

Explanation:

The complete equation would have to be P x V = n x R x T

where n is the number of moles, and if it is not clarified it is because they remain constant, as the question was worded.

On the other hand, the symbol R refers to the ideal gas constant, which declares that a gas behaves like an ideal gas during the reaction, and its value will always be the same, which is why it is called a constant. The value of R = 0.082.

The ideal gas model assumes that the volume of the molecule is zero and the particles do not interact with each other. Most real gases approach this constant within two significant figures, under pressure and temperature conditions sufficiently far from the liquefaction or sublimation point. The real gas equations of state are, in many cases, corrections to the previous one.

The universal constant of ideal gases is not a fundamental constant (therefore, choosing the temperature scale appropriately and using the number of particles, we can have R = 1, although this system of units is not very practical)

it's c (engineer's do their work with mechanical stuff not on any living being)