Scurvy is a difficiency disease caused by a lack of Vitamin C in the diet.

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.

Clouds are categorized based on their shape, size, and altitude. Stratus clouds are low-altitude clouds characterized by horizontal layering with a broad flat base. When stratus clouds occur on the ground the result is fog.

Heredity is the passing on of physical or mental characteristics genetically from one generation to another. Heredity is made possible via large strings of chromosomes which carry information encoded in genes.

Arteries are thick-walled because they carry oxygenated blood at high pressure, veins are comparatively thin-walled as they carry low-pressure deoxygenated blood.