Explanation:

* Stability: CH4 is a stable molecule with four single bonds between the carbon atom and four hydrogen atoms. It has a complete octet of electrons around the carbon atom, fulfilling the octet rule.

* Reactivity: CH3 is a highly reactive species called a radical. It has an unpaired electron on the carbon atom, making it very unstable and eager to react with other molecules to complete its octet.

* Bonding: In CH4, the carbon atom is tetrahedrally bonded to four hydrogen atoms. This tetrahedral geometry is very stable and contributes to the molecule's overall stability.

In nature, methane is found in:

* Natural gas deposits

* Biomass

* Atmospheric gases

* Biological processes (e.g., digestion in animals)

Methyl radicals are highly reactive and transient species, making them difficult to isolate and observe in nature. They are often formed in chemical reactions and can play a role in various processes, but they do not exist independently for extended periods.

Therefore, due to its stability and the presence of a complete octet, CH4 (methane) is much more likely to exist in nature than CH3 (methyl radical).