Is there any difference between green tea, and the black tea?

Green tea is made solely from the leaves of Camellia sinensis that have undergone minimal oxidation during processing. Green tea originates from China and has become associated with many cultures throughout Asia. The regular green tea drinkers may have a lower risk of developing heart disease
and certain types of cancer. As long ago as 4,000 years, 
China's inhabitants cultivated and drank green tea. Green
tea has been used as both a beverage and a method of traditional medicine in most of Asia, including China, Japan, Taiwan, and few others.
There are three main varieties of tea, green, black, and oolong. The difference between the teas is in their processing. 
Green tea is made from not fermented leaves.
Green tea is processed and grown in a variety of ways, depending on the type of green tea desired. As a result of 
these methods, maximum amounts of polyphenols and antioxidants are retained, giving maximum green tea benefits. The secret of green tea lies in the fact it is rich in catechin polyphenols, particularly epigallocatechin gallate (EGCG). EGCG is a powerful anti-oxidant.
The Chinese have known about the medicinal benefits of 
green tea since ancient times, using it to treat everything
from headaches to depression.
Green, oolong, and black teas all come from the leaves of 
the Camellia sinensis plant.
What sets green tea apart is the way it is processed.
Green tea leaves are steamed, which prevents the EGCG compound from being oxidized. By contrast, black and
oolong tea leaves are made from fermented leaves, 
which results in the EGCG being converted into 
other compounds.

Is there any  difference between green tea, and the black tea?

Both come from the same plant (Camellia sinensis), but the difference is in the processing. Green tea is dried, but not fermented. The shorter processing gives green tea a lighter flavor than black tea.
The flavor of green tea can be described as: fresh, light, green, or grassy. Some varieties of green tea are have a bit of sweetness to them, and some are a little astringent.
Green tea is not usually served with milk or sugar.
The best part is that it is safe for anyone of any age.
It’s just green tea after all.