What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

What has many keys but can’t open a single lock?

John was piloting a plane behind a car but was never able to overtake it. Why?

I’m orange, I wear a green hat and I sound like a parrot. What am I?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

If,

A = 1

B = 2

C = 3

...

...

Z = 26.

Based on above rule, you need to find an eleven letter word whose letter sum is equal to 52.

If eleven plus two equals one, what does nine plus five equal?

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

How many times can you subtract the number two from the number fifty?