Through which means can bacteria and other microorganisms enter the body?

Bacteria and other microorganisms can enter the body primarily through broken skin. When the skin is compromised, such as through cuts, abrasions, or other injuries, it provides a gateway for pathogens to bypass the body's first line of defense. The skin serves as a protective barrier, so any breach can create an opportunity for bacteria to invade and cause infections.

Clean skin generally maintains its protective properties, which helps prevent the entry of microorganisms. Intact nails and broken hair do not present openings for bacteria in the same way that broken skin does. Therefore, the primary route for bacteria and other microorganisms to enter the body is through areas where the skin has been broken.