Answer:
protein
Most genes contain the information needed to make functional molecules called proteins. (A few genes produce regulatory molecules that help the cell assemble proteins.) The journey from gene to protein is complex and tightly controlled within each cell.
Our cells reproduce so that we may grow and regenerate, the process of cellular reproduction is also the basis for human reproduction. Cellular reproduction is a means of creating new life.
Gas exchange is the delivery of oxygen from the lungs to the blood stream, and gets rid of carbon dioxide from the blood. It occurs in the lungs between the alveoli and a group of capillaries.