Final answer:
The two functions have in common that they are linear. They differ in that one is linear and the other is quadratic. Hence the correct answer is option A
Step-by-step explanation:
A characteristic that the two functions f(x)=x and g(x)=x² have in common is that both are linear functions. This means that the graphs of these functions are straight lines. However, a characteristic that distinguishes between them is that one is linear while the other is quadratic. The linear function f(x)=x has a constant rate of change and the graph is a straight line with a slope of 1. On the other hand, the quadratic function g(x)=x² has a varying rate of change and the graph is a parabola.
Hence the correct answer is option A