
Homeostasis refers to a system's ability
to regulate its INTERNAL environment.
The Big Bang Theory Season 6, Episode 2

No, he cut open a tauntaun and used
its INTERNAL body heat to warm him up.
The Big Bang Theory Season 2, Episode 23

(SIGHS) Can it be more of
an INTERNAL struggle?
The Big Bang Theory Season 10, Episode 7

If you want, I can call Internal Affairs,
Money Heist Season 1, Episode 11

I'm plagued by an INTERNAL struggle.
The Big Bang Theory Season 8, Episode 6