Answer;
-Partial pressure.
The scientist is most likely measuring the partial pressure of the gases in the atmosphere.
Explanation;
The pressure exerted by an individual gas in a mixture is known as its partial pressure. Assuming we have a mixture of ideal gases, we can use the ideal gas law to solve problems involving gases in a mixture.
Dalton's law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases, such that the partial pressure of each gas is the pressure that the gas would exert if it was the only gas in the container.
