What goes up but never comes down?

The following four words might seem abrupt to you. But you can make them meaningful by just adding vowels.
RDSH
GGPLNT
TMT
NN

Hint: All of them are vegetables.

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?

I am not a bull but I have horns.
I am not an ass but I have a pack saddle.
Wherever I go, I leave silver behind me.

Who am I?

What word begins and ends with an E, but has only one letter?

Can you decipher the following common phrase?

T M C
A U O
H S M
W T E

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

Irene killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Below the four parts have been reorganised. The four partitions are exactly the same in both arrangements. Why is there a hole?

Three friends named Mr. Black, Mr. Yellow and Mr. Green enter a pub on a weekend night. They are wearing either a Black, Yellow or Green shirt.

Mr. Yellow says to them, 'Did you notice that we all are wearing different color shirts than our names?'

To this, the man who was wearing the Green shirt said. 'Wow, thats right.'

Can you identify who is wearing which colour shirt ?