Which scenario illustrates how hair keeps you healthy and free from germs?
A person with a thick head of hair usually get fewer colds than someone who is bald because their head stays warmer during.
A person with thicker nose hairs probably filters out more dust and irritants from their lungs than those with thinner nose hairs. (MY ANSWER)
A person with excess body hair often stays healthier than one with very little hair since less dirt gets onto their skin.
A person with thick eyebrows will have better eyesight since the hairs better protect the eyes from damaging sunlight.
Sounds good to me. I really don't know, but your answer makes sense.
I do know that a great deal of body heat escapes through the head, so thicker hair will keep someone warmer (as will a hat), but that has nothing to do with colds and flu viruses.