Final answer:
Physical dependence refers to the physiological need for a drug, accompanied by withdrawal symptoms when the drug is discontinued. It involves changes in normal bodily functions and can lead to tolerance.
Step-by-step explanation:
Physical dependence refers to the physiological need for a drug, accompanied by unpleasant withdrawal symptoms, such as pain and cravings, when the drug is discontinued. Physical dependence involves changes in normal bodily functions and the user will experience withdrawal from the drug upon cessation of use. Tolerance is linked to physiological dependence and occurs when a person requires more and more drug to achieve effects previously experienced at lower doses.