I need help with finding the independent variable and dependent variable in the scenario…

I need help with finding the independent variable and dependent variable in the scenario down below.
A researcher was interested studying ways to encourage students to be more likely to volunteer their time helping out with community service projects. She created an experiment to determine whether educating students about the health benefits of community volunteering would influence their likelihood of volunteering to participate in a community service project. Two hundred students were randomly assigned to one of the following two groups.
Students in the “Video-Presentation” group watched a video presentation titled, “Volunteering Can Be Good For Your Health.” This video described physical and mental health benefits associated with community volunteering. After watching the video, each student was given the opportunity to sign-up to volunteer 2 hours of his/her time on a community service project.
Students in the “No-Presentation” group did not watch the video. Each student was, however, given the opportunity to sign-up to volunteer 2 hours of his/her time on a community service project.
In each of the groups, the researcher counted up the number of students who signed-up to volunteer for the community service project.