Ms. owens class was studying magnets Ms. Owens showed her students how to make an electromagnet using a nail, a D-cell battery, and plastic coated wire. The students wrapped the wire around the nail and then attached the ends to the battery. When they were finished, they tested their magnets by investigating how many paperclips their magnets could pick up. They also tested whether they could increase the strength of their electromagnets by using more coils of wire. They recorded the class average of their results in the data table seen here. Ms. Owens asked her students to graph their data in a line graph. How should the students label the x-axis on their line graph