An air mass is a large body of air that has similar moisture (density) and temperature characteristics. A front is a transition zone between two air masses.

The law of reflection specifies how waves, including light waves, bounce off of surfaces. Specifically, the angle of incidence of the approaching wave is equal to the angle of reflection of the reflected wave as measured from a line perpendicular (90°) to the surface.

An element is matter than cannot be separated into different types of matter by ordinary chemical methods.

Like decomposers, scavengers also break down the dead bodies of plants and animals into simple nutrients. The difference is that scavengers operate on much larger refuse and dead animals (carrion). Decomposers then consume the much smaller particles left over by the scavengers.

The cerebrum is the major part of the brain and is responsible for the main senses (thinking, hearing, seeing).