Answer:
What has keys but no locks, Space but no room, You can enter but you canβt exit.
The thinkers usually hold this body part
It speaks without a tongue, and listens without ears.
What is filled with air and sometimes a gas, tied to a string and often seen on your birthday?
The more you have of me, the less you see. Who am I?
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?