That's a loaded question. Well to me, through what I have heard from others and theories, I imagine there was other universes before us. It wasn't just nothingness, there was another universe, perhaps in another dimension that either ended or is still around today. Alternate dimensions are a theory, so it was probably just a matter of when ours would be born. We could've been the result of reaching the singularity in a black hole or we could've been the continuation of a grand generation of universes. Either way, I think before us there was other things that filled the void of darkness that we imagine to be before us.
If John goes running around his neighborhood everyday after work, the health-related factors that he will be improving through this type of training is any factors that involve the improvement of cardiorespiratory systems. This would improve a lot such as his circulation, endurance, stamina, and etc. Hope this helps.
An animal doesnt have a chloroplast
It goes from Kinetic when it is at rest to potential on its way to the bottom. There is also friction but very few people care about that.