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

In contrast to the Celsius scale (measured in degrees centigrade) that fixes 0° at the freezing point of water and the Fahrenheit scale that uses 32°, the Kelvin scale fixes 0° at absolute zero (-273°C) which is the lowest temperature possible in the universe.

Chemical waste like excess water, minerals, and salt are filtered from the blood by the kidneys and secreted into the urine. Urine is transported from the kidneys to the bladder through ureters.

Work is performed on an object when an applied force causes displacement along the same vector. Measured in joules (J) or newton-meters (Nm), work is calculated by multiplying force times displacement: \(W = \vec{F}\vec{d}\)