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

Part of the peripheral nervous system, the somatic nervous system is made up of nerve fibers that send sensory information to the central nervous system and control voluntary actions.

The traits represented by genes are inherited independently of each other  (one from the male and one from the female gamete) and a trait can be dominant or recessive.  A dominant trait will be expressed when paired with a recessive trait while two copies of a recessive trait (one from each parent) must be present for the recessive trait to be expressed.

Absolute zero is the coldest possible temperature in the universe. In the Kelvin scale, absolute zero is 0K and in the Celsius scale it is -273°C.

Cirrus clouds are thin, wispy high-altitude clouds composed of ice crystals that originate from the freezing of supercooled water droplets. Cirrus clouds generally occur in fair weather and point in the direction of air movement at their elevation.