What’s the difference between black and green teas?

Both green tea and black tea are made from the leaves of the same plant Camellia sinensis and both are hand-plucked. But there comes a difference…Green tea leaves are immediately steamed or baked after harvest, and then rolled and dried. They retain a green colour.
Black tea is also hand plucked, but then it is left to wither and oxidise (it is called fermentation among producers). Then the leaves are rolled and left to wither some more. After that they are dried and sorted as for green tea.
Black teas usually undergo full oxidation, and the results are the characteristic dark brown and black leaf, the typically more robust and pronounced flavors of black teas.
Green tea is allowed to wither only slightly after being picked. Then the oxidation process is stopped very quickly by rapidly heating the leaves.
Another question is which one these kinds of tea is healthier?
In many studies during a long perioud of time black tea favored over green,because:
1) it reduces the risk of heart disease
2) the flavonoids in black tea helped reduce the production of LDL – the “bad” cholesterol that can lead to stroke and heart attacks.
3) drinking black tea can help reverse an abnormal functioning of the blood vessels that can contribute to stroke or heart attack
But this doesn’t mean that green tea is bad for your health. So drink as much as you want.