Biking is Definitely Exercize

An hour ago I embarked on a journey to my school on my bike. I live about 3 miles from it and it's downhill on the way there. Unfortunately, on the way back, there is no downhill at all and it is a harsh hill. It only took me about 10 or 15 minutes to get there, but I think it took about 20 or 25 minutes to get back. My legs sure got exercise. I went on this journey to see how long it might take me to ride to school in the morning. My mom says I can bike to school next year, but it will probably be very hard to get home in the afternoons with heavy binders on my back up that long, steep, hill.