The heart is the organ that drives the circulatory system. In humans, it consists of four chambers with two that collect blood called atria and two that pump blood called ventricles. The heart's valves prevent blood pumped out of the ventricles from flowing back into the heart.

The Fahrenheit scale fixes the freezing point of water at 32°F, the Celsuis scale at 0°C, and the Kelvin scale at 273K.

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.

The formula to convert from F° to C° is:

\(C° = {5 \over 9} (F° - 32)\)

plugging in our values gives:

\(C° = {5 \over 9} (-40 - 32)\)

\(C° = {5 \over 9} (-72) = {{-72 \times 5} \over 9}\)

\(C° = {-360 \over 9}\)

\(C° = -40\)

The cerebellum is a large cluster of nerves at the base of the brain that's responsible for balance, movement, and muscle coordination.