Question

Please help and explain why, so that I understand.

Answer 1

Hello there!

The number of people in different cities should be represented on a graph as Two-dimensional. 

I'll explain why: The number of dimensions you need on a graph is equal to the number of variables that you are studying. In this case, you have two variables in the study:

1)The number of people
2)The city where they live

You'll need a two-dimensional graph with two axes in which one of the axes represents the number of people and the other axis represents the city. If you were also studying the age of those people, you'll need one more dimension to include this new variable. 

Have a nice day!