A: The short answer is, you can.
However, each judge requires you to follow his or her own rules within their own court room. Every judge is different.
In the trial level courts in New York, known as the Supreme Court, there is always a uniformed court officer assigned to every trial part. In addition to providing security for the court, he or she will assist in the orderly handling of exhibits and documents between the attorney and the witness.
There's no real reason this is done. It's just as easy for the attorney to walk a few steps and hand a piece of paper to the witness to read, than it is for the officer to get up, go to the attorney, turn around and hand the paper to the witness. Some judges simply want a buffer between the attorney and the witness, especially in contentious cases.
I have had some litigants ask whether having a uniformed and armed court officer is a waste of taxpayer money where he's just a messenger handing papers up to the witness. In reality, he serves a dual purpose; to control the court room and keep a buffer between a witness and the attorney. Of course the attorney can walk up to the witness and ask questions (at least most judges permit that, although some require you to use a podium to ask questions).