Which of the following scientist proved that air and water were the primary sources of C, H, and O in plant tissue? 

French agriculturist J.B. Boussingault (1834) proved that air and water were the primary sources of C, H, and O in plant tissue. He was a French chemist and agronomist who made significant contributions to agricultural science, including the understanding of plant nutrition and the role of elements such as nitrogen in plant growth. His experiments in the mid-19th century helped to debunk the then-prevailing theory that plants obtained carbon from the soil, showing instead that they primarily derive it from carbon dioxide in the atmosphere.