Which component is NOT primarily found in the air inside the International Space Station?

The correct answer indicates that helium is not primarily found in the air inside the International Space Station. The atmosphere within the International Space Station is carefully controlled to support human life and mainly consists of oxygen and nitrogen, with traces of carbon dioxide. Oxygen is essential for breathing, forming a significant part of the atmosphere onboard. Nitrogen is included to mimic Earth’s atmosphere and help maintain pressure.

Helium, while it may be present in small amounts, is not a significant component of the station's atmosphere. It is typically used in other applications, such as in the cooling of certain scientific instruments or in gas mixtures for specific purposes, but it does not constitute a primary part of the breathable air for the astronauts aboard. The air composition is critical for the health and safety of the crew, focusing mainly on oxygen, nitrogen, and controlled amounts of carbon dioxide.