阅读下文并回答问题。
Colorful fruit and vegetables are good for our health．Their natural colors help protect our bodies from disease．Think about the colors of fruit and vegetables：the red of tomatoes，the orange of carrots，the green of kiwi fruit and the purple of grapes．
You can enjoy eating fruit and vegetables of all colors：green，yellow，orange，blue，purple and white．Each color is unique(独一无二的) and important to our health．These colors work together to protect our bodies．Scientists have studied them and discovered the good of colorful fruit and vegetables．The list below shows the good of some colors in fruit and vegetables：
*Red gives us a healthy heart．It can reduce the risk of heart disease．Red helps prevent cancer and improve our memory．
*Yellow gives us a healthy immune system（免疫系统）．It is also good for our eyes．
*White can keep cholesterol（胆固醇）at a low level．
*Green helps prevent cancer．It is good for our eyes，too．It also gives strong bones and teeth．
*Blue helps us keep a good memory as we grow old．It also helps fight cancer and heart disease．
So when you are buying or eating fruit and vegetables，remember： try different colors of fruit and vegetables．
How many kinds of fruit and vegetables are mentioned in this passage?
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How do the colors of fruit and vegetables protect our bodies according to the passage?
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Does blue help us keep a good memory as we grow old?
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