What to grant to user to use index of table while querying?

Question

I want to know if oracle uses index when user queries data from table and that user has been granted just:
grant select on table to user

I want to know if it is needed some another grant to use index.

Answer 1

No, there is no requirement (or ability) to grant access to an index. If the user can access the table then their queries can use any available index.