I love yoga I do it 3 times a week it is so peaceful and great for your mind and spiritual practices. 
Whats yoga?
Yoga is like exercise but it is also a way to not only stretch and workout it is for physical and mental practices. 
Who originated yoga?
Yoga was originated in ancient India I can't believe you never heard of yoga. 
You cant belief there are other stuff you have never heard too.So are there techniques of performing yoga?
There is different types of yoga types the main ones are Hatha and Raja yoga and there is lot's of things we all have not heard of but this is a common.
Ok ,i am only curious to know more! Are there particular diet one needs to be effective in yoga?
I have never done the technique personally but friends have and they told me that Hatha yoga is great  for diets and taking supplementary physical technique practice. 
Is it done as a form of religious practice or believes?