Running backs

Question
I'm not sure if you understood my question.  Let me clarify: in NFL football, NCAA football, and high school football, during running plays, is the primary role of the player who is labeled as "running back" in the depth chart to carry and advance the ball?  (I'm asking about his PRIMARY role during running plays, meaning the role he plays most of the time in running plays, without implying that his other roles are unimportant.)

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Followup To
Question -
Let me start off by saying that I've already asked too many questions at two other forums so I'm taking my questions to the high school football forum, even though my main concern is NFL.  My question isn't limited to information(s) about high school football, so let me apologize for that first.  Here's my question: in NFL football, NCAA football, and high school football, during running plays, is the primary role of a player labeled as "running back" to carry and advance the ball?
Answer -
Hi Michael!
There is a little more to being a running back than just carrying the ball.

During running plays, the primary role of a player labeled as "running back" is to carry, fake, block, and or advance the ball? If you have any more questions please let me know.
Your friend, Coach Louis.

Answer
Hi Michael!
I understand your question. There are two players labeied as running backs the full- back and the tailback. Most of the time we think of the tailback as the only running back. That is not true, they are both running backs.

During running plays, the primary role of the players who are labeled as "running backs" in the depth chart is not to carry the ball but to advance the ball? (This is their PRIMARY role during any play not just running plays).

We like to think of the running back as the man who carries the ball all the time during running plays but this is not his Primary role. His role is to advance the ball. This is the primary role of every player on offense! If a coach tells you that a running back's role is to carry the football, he is not looking at the whole picture.
If you have any more questions please let me know.
Your friend, Coach Louis.