The human brain is a vital part of life; however, many people do not understand the significance of this complex organ. The human brain is like other parts of the body. It grows, becomes stronger, weakens and dies. The brain goes through phases throughout life and there are some exercises people can do to keep it healthy and active. The brain grows and becomes stronger in the first two decades, then it begins to deteriorate and can contract diseases. People should learn tasks they can do early in their lives to reduce the chances of having an unhealthy brain and tasks to make an unhealthy brain healthier. The first few years of life are significant for a child's brain. Most brain development occurs in the first years of life, but can continue until a person reaches their twenties. The brain is close to adult size by the time a child reaches six years of age. The brain is born with cells that grow as children learn new concepts. The brain will begin to connect nerve cells and further connections will be established. These connections help children learn skills that will lead to new skills later in life. The younger brain has multiple small, tightly packed clusters of activity. The baby brain has more connections, but the young adult brain has longer clusters of activity. The adolescent brain, or young adult brain, is an interesting time when the brain goes through different phases. The portion of the brain located just behind the forehead, the prefrontal cortex, oversees decision making and reasoning. Teens don't have a fully developed prefrontal cortex, which means they don't have the best decision-making skills. Teens use the amygdala, the... center of the paper... high in cholesterol. All these factors lead to an unhealthy brain. One thing people should try to avoid is stress. Stress damages the part of the brain that controls emotions, memory and learning; the hippocampus. Avoiding stress and being less anxious and angry will lead to a healthier brain in life. Understanding how the brain ages is important for people to learn to keep it healthy. People should learn that younger brains are stronger and faster; but knowledge of the older brain can compensate for the slower speed. The brain has important stages that affect people throughout their lives. There are some things people should learn to do to keep their brain healthy and active, such as eating a healthy diet and exercising regularly. Keeping your brain active with enjoyable activities is another way to ensure a healthy brain for life.