Final answer:
Exposure to carbon monoxide elevates carboxyhemoglobin, reducing the amount of oxygen that can be transported through the body.
Step-by-step explanation:
Exposure to carbon monoxide elevates carboxyhemoglobin. Carbon monoxide has a greater affinity for hemoglobin than oxygen, so when carbon monoxide is present, it binds to hemoglobin preferentially over oxygen, reducing the amount of oxygen that can be transported through the body. This can lead to symptoms such as headaches and confusion, and long-term exposure can cause brain damage or death.