Magic Forums

Oxygen 65%
Carbon 18.5%
Hydrogen 9.5%
Nitrogen 3.2%
Calcium 1.5%
Phosphorous 1.0%
Potassium 0.4%
Sulfur 0.3%
Sodium 0.2%
Chlorine 0.2%
Magnesium 0.1%

With trace amounts of:

Boron, Chromium, Cobalt, Copper, Fluorine, Iodine, Iron, Manganese, Molybdenum, Selenium, Silicon, Tin, Vanadium, and Zinc.

So since oxygen is a gas every single one human's element is air. Our if you prefer mass or molecular composition, our mass is 57% water, our molecular structure is 65% water, on either scale the majority of our make up is water. So all humans are water.

Each and every one of us is made of dead stars, so we're all fire, and we have plenty of salts and metals, so we're all earth.

All that being said. You have no element in regards to the humorist elements. No one was ever assigned elements in humorism, the idea was to balance all four. Humorism was never intended to be magical, it was the medical "science" of its time.

In Elizabethan times people began associating the humors to different characteristics and foods, etc. I generally assume the idea that someone was choleric, they were fiery, easily angered, ambitious, etc. The idea must have spread from there that a person with those characteristics must be a generally choleric person, thus their "element" is fire. There is no correlation with said humors and magic though.