The R in CD-R means "READABLE" i m sure
R' or also known as R-prime can, but doesn't always have to be the original R. It's there to show you that you can place any other alkane substitute in that place. You will probaby also stumble...
The R-value of insulating material is an indication of its effectiveness in reducing heat flow through walls, floor, and ceiling of a structure.
It basically means that everybody is who they are, and it's based on gay studies.