Well there's Water, Earth, Fire, and Air. Not quite sure how this would be a school question. But here it is.
The nose, mouth, ears and eyes decide the entry of foreign particles. Little children mostly acquire it because mostly children put their hands or stick their tongues on nearby objects which are mostly infested with bacterias and pathogens, sometimes these particles are harmful and sometimes they aren't.
Answer:
Yes
Explanation:
Humans are good at it transferring energy from place to place.
