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.
Chemistry Astronomy Biology (I'm pretty sure... show more I am filling out my college application and I need at least one credit of a physical science class, but i have no idea what that means because I have never taken a class called physical science so are any of these classes considered physical science?