Which of the following was likely present in Earth's early atmosphere over four billion years ago? Abundance of oxygen Very cold temperatures Presence of inorganic molecules Low levels of ultraviolet radiation

Presence of inorganic molecules

Explanation:

This prediction is often debated as a part of origins of life.

Inorganic molecules do not contain carbon and cannot be considered as biological organism. One theory predicted that before the first life form exist, early atmosphere is covered in inorganic molecules. Over time, the interaction with inorganic molecules and lightning might cause a reaction that resulted in the formation of building blocks amino acids and nucleotide, which eventually evolved into living organism.