what does this mean RNA polymerase II

Question: what does this mean RNA polymerase II
- Keywords:
  gene,
  polymerase,
  rna
Asked by jamesbeilby to Marcus on 12 Nov 2012.
- Marcus Wilson answered on 12 Nov 2012:
  
  RNA polymerase II is a large group of proteins that work together in the cell to read DNA and make a copy of that DNA.
  
  Its called RNA polymerase II because the copy it makes is made out of RNA ( like DNA but shorter lived).
  
  It is called a polymerase because it puts simple building block letters of RNA together to form long strings of letters, making a copy of the DNA’s code. It makes sure to put the right letter (as it is in the DNA) in the copy, and it does this for thousands of letters! its a pretty impressive micro machine.
  
  and II (2) is because its the second one they discovered. there is also rna polymeras I and III, but II is the most important.( iwould say that!)

Question: what does this mean RNA polymerase II