Answer:
I run through hills. I veer around mountains. I leap over rivers and crawl through the forests. Step out your door to find me. What am I?
I smell like blue paint pours like green paint and I look like a red truck.
I have two bodies joined together as one. When standing still, I run and run. What am I?
I am carried by mad animals.
I am always in front of you but you will never see me
No matter how little or how much you use me, you change me every month.