The material identifies nicotine as the main smoke component that reduces oxygen transport in the blood.

### Why this is right The statement assigns the oxygen-transport effect to the wrong substance. The material identifies carbon monoxide as reducing oxygen transport, while nicotine is described as addictive and as affecting the nervous system. ### The concept Smoke contains multiple harmful chemicals, and their effects should not be confused. Nicotine is associated with addiction. Tar contributes to lung-tissue damage and cancer. Carbon monoxide reduces the blood's ability to carry oxygen. Recognizing these differences helps explain why smoke exposure can affect both respiratory function and oxygen delivery. ### The other options - **The statement is false**: Nicotine is associated with addiction and effects on the nervous system. The material assigns reduced oxygen transport to carbon monoxide. ### Watch out The fact that all three substances occur in tobacco smoke does not mean they have the same stated effect. ### Terms - **Nicotine**: An addictive tobacco substance that affects the nervous system. - **Carbon monoxide**: A gas in tobacco smoke that reduces oxygen transport in the blood. ### Remember Do not swap the effects: nicotine is linked to addiction, and carbon monoxide to reduced oxygen transport.