What goes up but never comes down?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

I taste better than I can smell. Who am I?

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

How can you leave a room with two legs and return with six legs?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

What will you call your mother's brother's brother-in-law?

Why is it against the law for a man living in Delhi to be buried in Mumbai?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?