What is the main effect of carbon monoxide (CO) exposure on the human body?

The main effect of carbon monoxide (CO) exposure on the human body is that it restricts the body's ability to absorb oxygen. Carbon monoxide is a colorless, odorless gas that can interfere with the oxygen-carrying capacity of hemoglobin in the blood. When CO is inhaled, it binds to hemoglobin more effectively than oxygen does, leading to reduced oxygen transport throughout the body. This can result in symptoms such as fatigue, headaches, dizziness, and in severe cases, can be life-threatening due to the lack of oxygen available for vital organs.

In contrast, the other options incorrectly suggest positive effects on energy levels, cognitive function, and respiratory function, which do not occur with CO exposure. Understanding the harmful consequences of carbon monoxide is critical for recognizing the dangers associated with its presence in the environment and for implementing appropriate safety measures.