Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

I cry without having a voice.
I fly without having wings.
I bite without having teeth.
I whisper without a mouth.

Who am I?

Who always enjoys poor health?

How many letters are in the alphabet?

Which of the following words don't belong in the group and why?
CORSET, COSTER, SECTOR, ESCORT, COURTS

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

Rectify the following equality 101 - 102 = 1 by moving just one digit.

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

What word is represented by this rebus?