Since fish extract O2 from water, why can't man do it?

[Robert W]

Fish and other animals extract oxygen from water to survive. Who has a clue why man can't do it too?

Do you know of inventions that will let man do it for themselves? This would be an important invention. So would a system that stops men from getting the bends. Whales dive very deep. Seems a matter of time that man will also dive deep.

 

[1srelluc]

 

[toobfreak]

Fish and other animals extract oxygen from water to survive. Who has a clue why man can't do it too?

Because he's set up to breathe in air.

Do you know of inventions that will let man do it for themselves?

Yes.

So would a system that stops men from getting the bends.

Sure, that system would require people to STAY at depth and get used to living there.

Whales dive very deep. Seems a matter of time that man will also dive deep.

Whales dive deep because they are used to it and it is natural for them.