Final answer:
Nitrogen can be deadly when levels exceed 78% as it displaces oxygen in the air, leading to oxygen deficiency. While nitrogen itself is not toxic, lack of oxygen can have serious health consequences.
Step-by-step explanation:
Nitrogen can be deadly when levels exceed 78% because it displaces oxygen in the air. While nitrogen itself is not toxic, high levels can lead to oxygen deficiency, which can be life-threatening. Oxygen is necessary for human respiration, and when nitrogen displaces too much of it, it can lead to symptoms such as dizziness, shortness of breath, and even loss of consciousness.
Learn more about Nitrogen's effect on oxygen levels in the air