The two largest veins in the body, the venae cavae, pass blood to the right ventricle which pumps the blood to the lungs through the pulmonary artery. Blood picks up oxygen in the lungs and returns it to the left atrium via the pulmonary vein.

Blood is created in bone marrow and is made up of cells suspended in liquid plasma. Red blood cells carry oxygen, white blood cells fight infection, and platelets are cell fragments that allow blood to clot.

Vitamins are necessary for a wide variety of bodily processes. Some vitamins like Vitamins A and C come from diet but others, like Vitamin D, are generated in response to sunlight.

An element in a solid state has atoms or molecules that are constricted and do not move freely. Solids maintain a constant volume and shape and exist at a lower temperature than liquids or gases.

The rate of vibration of sound is called frequency and is measured in hertz (Hz). One hertz is one repetition per second and sounds with high frequency have a higher pitch than sounds with lower frequency. Humans can hear sounds in the range of 20 Hz to 20 kHz.