Which of the following conditions remain constant in charles's law?
volume and pressure
density and temperature
pressure and number of moles
temperature and number of moles

Pressure and number of moles.

Explanation:

According to Charles law,

For an ideal gas, volume is directly proportional to temperature at constant pressure for a fixed amount of gas.

V ∝ T

From the law we can say that the two conditions are:

Pressure and number of moles

Explanation:

Charles law states that the volume of a given mass of gas is directly proportional to its absolute temperature provided its pressure remain constant. V = KT

k = V/T

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.