Final answer:
Primary colonizers such as Actinobacteria, Deinococcus, and Cyanobacteria were the first bacteria to establish themselves in a new environment according to molecular evolution analysis.
Step-by-step explanation:
Primary colonizers are the bacteria that are the first to establish themselves in a new environment. In the context of bacteria colonizing the human body, primary colonizers include Actinobacteria, Deinococcus, and Cyanobacteria. Actinobacteria are common Gram-positive bacteria that break down organic waste, while Deinococcus is a bacterium highly resistant to ionizing radiation, and Cyanobacteria are photosynthetic bacteria. These bacteria were the first to colonize land according to molecular evolution analysis.