The Sahara is a sandy desert with giant sand dunes. It covers over 3 million square miles of Africa. Other major deserts include the Arabian Desert in the Middle East, the Gobi Desert in Northern China and Mongolia, and the Kalahari Desert in Africa. Go here to learn more about the World's deserts.he Sahara is a sandy desert with giant sand dunes. It covers over 3 million square miles of Africa. Other major deserts include the Arabian Desert in the Middle East, the Gobi Desert in Northern China and Mongolia, and the Kalahari Desert in Africa. Go here to learn more about the World's deserts.
Addiction is a persistent, compulsive dependence on a behavior or substance. The term has been partially replaced by the word dependence for substance abuse. Addiction has been extended, however, to include mood-altering behaviors or activities.
â¢ addictive drug â a drug that is both rewarding and reinforcing. â¢ dependence â an adaptive state associated with a withdrawal syndrome upon cessation of repeated exposure to a stimulus (e.g., drug intake)