What does below science rebus mean?

Ag Ag Ag
Ag SPOON Ag
Ag Ag Ag

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111

You have two rectangular wires.

Both of them have property that when you light the fire from one end , it will take 60 minutes to get completely burn.

However, they do not burn at consistent speed (i.e it might be possible 1st 20% burn in 50 minutes and 80% can burn in 10 minutes).

So how could you measure 45 minutes ?

How many times do a clock's hands overlap in a day ?

The more it dries, the wetter it becomes. Can you tell what it is?

Replace the question mark in the picture below.

John was born on March 5, 1970, in Delhi, India. Jacob was born 25 days before John. The year when they took birth, Republic Day fell on Monday.

Can you find out on what day was Jacob born?

Can you find out the number of the parking space in which the car is parked?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?