What does below science rebus mean?

Ag Ag Ag
Ag SPOON Ag
Ag Ag Ag

What has 13 hearts but no other organs?

I welcome the day with a show of light, I stealthily came here in the night. I bathe the earthy stuff at dawn, But by noon, alas! I'm gone.

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

Which point will the car reach to go out?

A man is lying dead in a field where no one is around. His head is split open and his legs are disfigured. Near to him, there is an unopened package. No living organism can be found anywhere at the crime scene.

How did he die?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

I taste better than I can smell. Who am I?

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