A controlled experiment is when scientests go throw thests to make an experiment
There are many processes to get nuclear energy. Nuclear energy is basically energy from an atom. For example fission is where the nucleus of an atom ( typically radioactive atoms ) gets split then energy is released ( typically heat). And in radioactive decay radiation is released from an radioactive atom. Hope this helps
Photosynthesis in plants converts solar energy into chemical energy using electrons and protons from water.
Pressure decreases with increasing altitude. The pressure at any level in the atmosphere may be interpreted as the total weight of the air above a unit area at any elevation. At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels.