What has one letter and starts with an E?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

A person was found dead on a big green land with no trees or buildings around. When the police arrived, they found a piece of rock lying next to him and the man was wearing clothes comprising of red, blue and yellow colours.

Can you tell who the person is and what was the cause of death?

What word begins and ends with an E, but has only one letter?

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

1 rabbit saw 9 elephants while going to the river. Every elephant saw 3 monkeys going toward the river. Each monkey had 1 parrot in each hand. How many animals are going towards the river?

He does not have any heart but still, He manages to live.
If you kill him, you will eventually die but yet you kill him.
He cannot run, who is He?

I die but do not live. What am I?

What has to be broken before you can use it?