The four most common chemical elements found in living matter are 1,C, H,O, P
2,C, H,O, N
3,C, H,N, P
4,C, H,O, S
5,C, H,O, Ca​

Explanation:

In all living system we can always find basic elements carbon, oxygen, nitrogen and hydrogen, carbon is the basic building unit contained in living matter. The percentage of carbon in the mass of living matter is 19.0% oxygen and hydrogen are present in almost all organic compound which creates living organisms.

well first you need the sample of the temperature and gas level. i couldnt write a hypothesis unless i had some data. i think temperature changes will effect volumes of gas because gas changed into a solid or liquid at specific temperatures.

actually the answer is c