Index Of Pattycake (jpg) -html -php -asp -htm -jsp What Is The Difference Between Option On Stock Index And Option On A Stock Index Future?

What is the difference between option on stock index and option on a stock index future? - index of pattycake (jpg) -html -php -asp -htm -jsp

I understand this option. But what is the difference between options on futures on stock indexes and options on stocks in the index?