Why wasnt Oxidation chemical weathering common 2 billion years ago

Oxygen levels were a lot lower then

Explanation:

2 billion years ago was before the Great Oxidation Event. The first oxygen-producing cyanobacteria did not exist before then. Without oxygen, oxidation cannot be common.

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.