Take a small burning candle. ... After few minutes the candle is extinguished. As the supply of air is stopped due to glass jar the burning of candle is also stopped. This experiment proves that air supports burning.
Answer:
It hit Earth like a really long time ago, so many rocks and soil should have been piled on top of the crater because of wind, rain, etc.
Also, it is really deep and really old so when it is old, it gets less visible to the naked eye.
C because of the positioning of the initial ray of refraction
The charge of the copper nucleus is 29 times the charge of one proton:

the charge of the electron is

and their separation is

The magnitude of the electrostatic force between them is given by:

where

is the Coulomb's constant. If we substitute the numbers, we find (we can ignore the negative sign of the electron charge, since we are interested only in the magnitude of the force)