The carbon cycle represents the ciruit of carbon through Earth's ecosystem. Carbon dioxide (CO₂) in the atmosphere is absorbed by plants through photosynthesis. Plants then die and release carbon back into the atmosphere during decomposition or are eaten by animals who breathe (respiration) the carbon into the atmosphere they exhale and produce waste which also releases carbon as it decays.

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

An exoskeleton (external skeleton) is common in arthropods like insects, spiders, and crustaceans.

Mantle makes up 84% of the Earth's volume and has an average thickness of approximately 1,800 miles (2,900 km). It is dense, hot, and primarily solid although in places it behaves more like a viscous fluid as the plates of the upper mantle and crust gradually "float" along its circumference.

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