Each tonsil consists of a network of crypts (pits) that store cells used to fight infection. The tonsils contain B cells, a type of white blood cell that fights infections. They also produce antibodies against polio, streptococcal pneumonia, influenza, and numerous other infections.
Global Warming: What's Up With The Weather? is a DVD presentation of the television special by NOVA and Frontline dealing with questions raised about modern climate change.
Weather is the state of the atmosphere at any given time and place, determined by such factors as temperature, precipitation, cloud cover, humidity, air pressure, and wind. The study of weather is known as meteorology. No exact date can be given for the beginnings of this science since humans have studied weather conditions for thousands of years. Weather conditions can be regarded as a result of the interaction of four basic physical elements: the Sun, Earth's atmosphere, Earth itself, and natural land-forms on Earth.