The basics of the communications theory is going to be about stuff like different types of AM,FM, digital etc modulation and all the maths behind it. The basics of the control systems theory is about the feedback control loops of systems to allow them to achieve a certain output.
I'm taking an electronics & communications degree and both modules are mandatory. Most EE degrees will probably do the same, but if you're tasked with choosing between them just go for whichever one you are personally more interested in - it won't particularly affect your career progression much as you should have a chance to learn both at some point, and you're much more likely to do well in a module that interests you.