Which one can be replaced????

Well,man requires air,water and food to live,i was wondering with global warming and other factor which one of our need can be eliminated or replaced completely,i think food can be replaced as we can live without food for few days!!!!

Yes, I agree on food as well. We certainly don't need to produce so much. It just takes proper allocation (a hint to those with an overweight problem).

Water is our most precious resource. At least we can extract oxygen out of it too 😉

I would really say none of them. So far alternate means of resources and generation of the items have been mentioned. You are still being dependant on the resource. Air, nutrients, water & a supportive environment cannot be replaced however the technology for providing these can adapt.

i go with gohm we can replace nothing .😎

Ok guys,but i think we can replace food in the beginnigh we can introduce some supplements which can equip our body to generate required nutreints!!!!