Answer :

In the atmosphere, carbon is primarily found in the form of carbon dioxide (CO₂).

Carbon dioxide (CO₂) is a colorless and odorless gas that is naturally present in Earth's atmosphere as a trace gas. It consists of one carbon atom covalently double bonded to two oxygen atoms.

Here’s a detailed breakdown of the other options for better understanding:

1. C₆H₁₂O₆ (Glucose): This is a sugar molecule and a form of carbohydrate. It is not found in the atmosphere but rather in living organisms, where it serves as a major energy source.

2. H₂O (Water): Water in its liquid or vapor form is found in the atmosphere as part of the hydrosphere. While it contains hydrogen and oxygen, it does not contain carbon.

3. ATP (Adenosine Triphosphate): ATP is a complex organic chemical that provides energy to drive many processes in living cells. It is not found in the atmosphere but within living organisms.

Given these options, the correct form in which carbon is found in the atmosphere is carbon dioxide (CO₂).