Questions

Firstly, I focussed on "If you remove my 1st & 2nd letters, you can't see me". The first thing that comes to mind which we can’t see is the "AIR".

So now, what 4 letter words can be formed ending with "AIR"? Think of all the words from A to Z, considering which one lies above you. That is how we get to "HAIR".

Now, which 5 letter word can be formed ending with "HAIR"? Starting with A to Z, we reach "CHAIR" and also, it lies below us.

And the required answer is "CHAIR".

A group of emus is called as a mob. Emus is a kind of bird which is next to ostrich in its size.

Arunachal Pradesh is called The Orchid Paradise in India.

Ostrich

Sourav Chandidas Ganguly was a former Indian Cricket team captain mostly called as DADA.

One way is shorting the two inputs of the NAND gate and passing the input.

truth table:

A B output

1 1 0

0 0 1

The second way is passing the input to only one input (say A) of the NAND gate. Since the other input  (say B is floating, it is always logic one.

Truth table:

A B output

1 1 0 

0 1 1