Will we, people, be able to colonize Mars? And if so, how will we produce oxygen, water and grow food once there?

Could a future Martian colony become self sufficient ? I am thinking mainly of power generation, ability to make air to breath, water , growing food, mining metals and chemicals from the surface.

Do Martians eat meat?

Will Martians eat people?

IS there water on mars? FYI the ice caps there are made of dry ice not H2O