How is the graph of a function whose domain is all real numbers different from the graph of a function whose domain is a specified set of distinct numbers?

Domain is all first components of ordered pairs, while range is second component of ordered pairs. Real numbers include natural numbers, integers, whole numbers. If the domain is all real numbers this means the x correspondence but be any and all real numbers. Range means y is 2. The answer is a horizontal line drawn at y intercept 2