Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

What kind of tree can you carry in your hand?

What Time Should the last watch show in the below figure?

What month of the year has 28 days?

What have one eye but still cannot see?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

I am the first thing you need while camping.
I am always with the person named Marcos Valencia and Carrick.
But Pogba Zlatan and Rooney think I am wasteful and do not need me.
I am the second to the last thing to add when you are making a patch.

What am I?

You are in a room with no metal objects except for two iron rods. Only one of them is a magnet.
How can you identify which one is a magnet?

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