What do theories hypothesize about the conditions of earth's early atmosphere? little to no oxygen low levels of ultraviolet radiation protective atmosphere very cold temperatures

Little to no oxygen

Explanation:

Little to no oxygen is a theory that hypothesize about the conditions of Earth's early atmosphere.

the sphincter muscles at the end of the digestive tract is the anus.

in a chemical reaction, the atoms and molecules produced by the reaction are called products. no new atoms are created, and no atoms are destroyed. in a chemical reaction, reactants contact each other, bonds between atoms in the reactants are broken, and atoms rearrange and form new bonds to make the products.