According to the geological time scale,
mammals
evolved after the first insects evolved.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago.

Explanation:

the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

prism b but im not for sure

this protocol provides a detailed procedure for total protein extraction for western blot analysis from achieved samples following trizol isolation of rna.