Which two properties do change with altitude?

As altitude increases, the amount of gas molecules in the air decreases—the air becomes less dense than air nearer to sea level. Thin air exerts less pressure than air at a lower altitude

i believe the correct answer from the choices listed above is the first option. the scientists need to look at the   validity of data, claims, hypotheses, and observations before  developing an argument. they base their arguments on facts that are present and they make sure they have proofs. 

explanation:

it would be heredity