Is there a difference between anoxia and hypoxia because I checked the Internet and all I got was that hypoxia is an extreme form of anoxia where there is an inadequate O2 supply despite an adequate blood supply. Then why have 2 terms that mean the same thing.

Anoxia is the extreme form of hypoxia. We need both words because the first is a total depletion, and the second is just a decrease below adequate levels.

 

Just like we need both of the words "non-existent" and "inadequate". There's a difference between nothing and not enough.

Thanks for the very clear explanation.

You're very welcome.