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.
Students with a limited background in the sciences may consider courses that address a physical science from a conceptual and modern perspective. Students in these courses learn the basics of many areas of physical science, including astronomy, physics, geology and chemistry. These very basic courses are designed to prepare students for the successful completion of beginner-level courses in the physical sciences.