Please Can Anyone Explain

[Della]

Can anybody explain:
1. What are Velus hairs and do they ever grow?

2. I saw a picture of Intermediate Hair and it was just like mine which I thought was my hair breaking off. So what is Intermediate Hair and does it grow longer?

3. I have pure white translucent hairs started growing but they won't take dye either permanent or temporary so they make me look even more bald so I have to brush brown mascara through them.

What are these hairs and will they carry on growing.

Any help would be gratefully appreciated.