The diaphragm is a system of muscles that allows breathing. During inhalation, the diaphragm expands and air rushes in to fill the space created. Then, during exhalation, the diaphragm contracts and forces the air back out.

Decomposers (saprotrophs) are organisms such as bacteria and fungi that break down the organic matter in the dead bodies of plants and animals into simple nutrients.

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.

Power is the rate at which work is performed or work per unit time: \(P = {w \over t}\) and is measured in watts (W).

Tertiary consumers eat primary consumers and secondary consumers and are typically carnivorous predators. Tertiary consumers may also be omnivores. Examples include wolves, sharks, and human beings.