What is so special about green tea? The Chinese and Indians ＿＿（21）＿＿ it for at least 4,000 years to treat everything from headache to depression. Researchers at Purdue University recently concluded that a compound in green tea ＿＿（22）＿＿ the growth of cancer cells. Green tea is also helpful for infection and damaged immune function. The secret power of green tea is its richness in a powerful anti-oxidant. Green tea and black tea come from the same plant. Their ＿＿（23）＿＿ is in the processing. Green tea is dried but not fermented, and this shorter processing gives it a lighter flavor than black tea. It also helps retain the tea’s beneficial chemicals. That is why green tea is so good for health. The only ＿＿（24）＿＿ negative effect of drinking green tea is a possible allergic reaction and insomnia due to the caffeine it contains.