An endogenous infection is from biological material in one part of the body, where it is safe, intruding into a part of the body, where it can do harm - (stomach acid in the chest cavity, faecal matter in the blood etc) Just a guess!!

what is an endogenous promoter

The enzymes created by body itself are endogenous enzyme?

An endogenous tree is a tree that is native to your area

Endogenous is an adjective to describe something produced or growing from within; originating internally.

Example:

The design is endogenous; I've been working it out in my head for a long time.