Once food has reached the sea floor, currents carry this food and organisms filter it without having to use their own energy to go and get food. Another way organisms use energy is by coming out at night and rising to feed on upper-level organisms.
Physical Science redirects here. It is not to be confused with Physics. Physical science is a branch of natural science that studies non-living systems, in contrast to life science. It in turn has many branches, each referred to as a physical science, together called the physical sciences.
You could explore courses in management, teaching, research, finance/banking, media, corporate communications, retail, hospitality etc. You can also take the Civil Services as well as the Indian Forest Service Exams with Physical science as one of the papers in the Mains examination. The field is intellectually exciting, being rich in phenomena and ideas, and has emerged as one of the major growth areas of physics.