Carbon would be the answer to this because it is an element while water is a compound. In addition, carbon had 4 bonding sites which allows it to form a variety of molecules like sugars, proteins, and even DNA that are essential for life as we know it.
Explanation:
Carbon dioxide is added to the atmosphere naturally when organisms respire or decompose (decay), carbonate rocks are weathered, forest fires occur, and volcanoes erupt. Carbon dioxide is also added to the atmosphere through human activities, such as the burning of fossil fuels and forests and the production of cement.