1. Explain why it can be difficult to give up smoking
Nicotine is addictive causing you to want more.
1. Explain the effect of breathing in carbon monoxide on the function of the blood.
Carbon monoxide binds with red blood cells containing haemoglobin; this reduces the oxygen carrying capacity of the blood.
2. Explain how an antibacterial drug may become ineffective over time.
To treat bacterial infection antibacterial drugs are used. Antibacterial drugs many be overused so some bacteria resistant to the antibacterial drug may survive.