What Deficiency does the below rebus represent?

VIT_MIN

It is a nine-letter word.
The exact opposite of the phrase "friendly and outgoing"
It contains the word "over".
It starts will a vowel.

What is it?

I am white when I am dirty, and black when I am clean. What am I?

Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

There is a place where if I stand up straight, I will still be considered sideways.

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

The ages of a father and son add up to 66.
The father's age is the son's age reversed.
How old could they be?
(3 possible solutions).

A woman named Maria was at the funeral of her mother. She met a nice young man that she had never seen before and after the service, they spent a bit of time together. Then she got busy and didn’t get his name or phone number before he left. She tried to find him, but no one knew who he was or how to contact him. A few weeks later, Maria’s older sister dies and the police suspect murder. Who killed the sister?

Replace the question mark with the correct number.