Anything we do has some type of impact whether it be large or small--cause and effect. Therefore, perhaps you want to come up with a way to use less resources in your own life. You could then share your ideas with your class, through social media or word of mouth and perhaps others will do it also. What about trying to use mass transit, bicycles and walking instead of being driven by car whenever you do errands or go someplace? The amount of carbon dioxide, nitrous oxides and sulfur oxides will lessen just by your actions. This means less greenhouse gases and pollutants entering the atmosphere. Multiply that by all your friends, and their friends and it could certainly have a large impact. For the world at large, everything we do in our own small way can have a positive influence on the rest of our planet. You can do a recycling project, a random act of kindness project, you can publish something online, whatever--use your imagination.