Answer:
Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy.
Explanation:
Science
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.
Changes in groups of organisms over time produce variations in a population. This relates to both macroevolution and microevolution.
These are evolutions within a small group or a population and across the whole species.
This is extremely vague, but assuming this is regarding concentration gradient in the nervous system, the Sodium-Potassium pump is responsible for transporting sodium and potassium.