Do you know the difference between a sequence and a series?

Question

Graph the terms of an arithmetic series. Remember the domain is the set of natural numbers, not the set of real numbers. What type function do you see?
Graph the terms of a geometric series. Remember the domain is the set of natural numbers, not the set of real numbers. What type function so you see?
Someone asked me this but, I don't quite understand what they mean. I tried to find this information from a math book and found nothing. I was also asked to provide a real life example of both arithmetic and geometric sequence and series.