Washington Master Esthetics Practice Exam

Where do we get the nitrogen we need for survival?

1. Air

2. Water

3. Food

4. Soil

The correct answer is: Food

While nitrogen is indeed an essential element for life, the primary source where humans obtain the nitrogen necessary for survival is through food. Nitrogen is a critical component of amino acids, which in turn make up proteins, as well as nucleic acids like DNA and RNA. Our bodies cannot directly use nitrogen in its gaseous form found in the atmosphere. Instead, we rely on the consumption of plants and animals to intake nitrogen. Plants utilize nitrogen from the soil, which is assimilated into proteins during photosynthesis. When we eat these plants or any animal that has consumed plants, we are effectively obtaining the nitrogen needed for our body functions. In contrast, while air contains about 78% nitrogen, we cannot utilize it directly. Water does not contain nitrogen molecules in a form usable by the body, nor does soil serve as a direct source for human consumption when discussing nitrogen intake. Thus, food is the correct answer as it is the main way we acquire the nitrogen necessary to sustain life.