Se alimentan con sol y agua
The theory that is demonstrated by this experiment is natural selection.
Basically, only the strongest bacteria survived, and nature decided which of those bacteria were fit enough to get to live and reproduce in the future. Those bacteria that were "willing" and able to fight their way through a huge number of bacteria were the ones who ultimately won.
The answer should be A. A controlled nuclear chain reaction produces heat, driving steam turbines to produce energy.
