Answer:
I go up and down at the same time. Up towards to sky and down towards the ground. What am I?
No matter how little or how much you use me, you change me every month.
Everyone has me except for a few. You may not be able to identify me but I can always identify you. What am I?
The last man on Earth received a phone call, who was the caller?
Wind and cord combine, buzzing in the box. In all this we find, though to some the use is lost. What am I?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?