What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

A letter is hidden in the image in plain sight. Can you spot it in 6 seconds? Test your eye power now!

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

How many letters are in the alphabet?

It can be easily calculated that the digits 0 to 9 can be arranged into 3628800 distinct ten-digit numbers.

But do you know how many of these numbers are prime?

These types of puzzles are known as charades. What you have to do is find two words that are referred to in the first stanza and the second stanza and put them together to form the third word in the third stanza.

Just for example, if my first refers to 'off' and my second refers to 'ice', then my whole will be office.

My first is present - future's past -
A time in which your lot is cast.

My second is my first of space
Defining people's present place.

My whole describes a lack of site -
A place without length, breadth, or height.

What jumps when it walks and sits when it stands?

What is the riddle which can be asked all day with a different correct answer each time.

Lifeless eyes on my smiling face and watch your child's sleeping place. In their dreams they hold me tight. What am I?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?