Final answer:
Experiencing lethargy, impairment of coordination, and nausea occurs when the oxygen content in the air falls below 16% by volume, leading to hypoxia and reduced oxygen delivery to the body's tissues.
The Correct Option is: A) 16%
Step-by-step explanation:
A decrease in the percentage of oxygen by volume in the air can lead to symptoms of hypoxia, which include lethargy, impairment of coordination, and nausea. Specifically, when the oxygen content in the air falls below approximately 16% by volume, these symptoms can occur.
Normally, the atmosphere contains about 20% oxygen, which is essential for the body's energy production processes. However, as the percentage of oxygen decreases, it impairs the ability of hemoglobin in the red blood cells to transport oxygen to tissues and organs.
This can ultimately reduce the rate of oxygen delivery, which is critical for cellular metabolism and can lead to the aforementioned symptoms.
When the percentage of oxygen by volume in air falls below 16%, a person may experience symptoms such as lethargy, impairment of coordination, and nausea.