The legal drinking age is the minimum age at which a person can legally consume alcoholic beverages. The minimum age alcohol can be legally consumed can be different from the age when it can be purchased in some countries. These laws vary between countries and many laws have exemptions or special circumstances. Most laws apply only to drinking alcohol in public places with alcohol consumption in the home being mostly unregulated (an exception being the UK, which has a minimum legal age of five for supervised consumption in private places). Some countries also have different age limits for different types of alcohol drinks. The majority of countries have a minimum legal drinking age of 18. The most commonly known reason for the law behind the legal drinking age is the effect on the brain in adolescents. Since the brain is still maturing, alcohol can have a negative effect on the memory and long-term thinking. Alongside that, it can cause liver failure, and create a hormone imbalance in teens due to the constant changes and maturing of hormones during puberty. Some countries have an MLDA of 19 to prevent the flow of alcoholic beverages in high schools, while others like the United States have a MLDA of 21 in an effort to reduce the amount of drunk driving rates among teenagers and young adults. Africa The most common minimum age to purchase alcohol in Africa is 18. However, Angola (except Luanda Province), Central African Republic, Comoros, Equatorial Guinea, Guinea-Bissau, Mali, and Togo have no laws on the books restricting the sale of alcohol to minors. In Libya, Somalia and Sudan the sale, production and consumption of alcohol is completely prohibited. Americas In Central America, the Caribbean, and South America the legal drinking age and legal purchase age varies from 0 to 20 years (see table below). In South America in particular, the legal purchase age is 18 years, with two exceptions: In Paraguay, the legal drinking age and purchase age is 20 years. In Guyana, minors aged 16 or 17 may consume a glass of beer or wine in a restaurant provided they buy a meal. In North America the legal drinking age and legal purchase age varies from 18 to 21 years: In Mexico, the drinking age is 18 in all states. In the United States, the minimum legal age to purchase alcoholic beverages is 21 years of age; the