I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

In the picture given below, can you find out which digit will take place of the question mark?

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

A couple went on a climbing trip. But only the husband returned from the vacation and said that his wife slipped off while climbing and died. On investigating, the local sheriff arrested him saying, 'Your travel agent called. You murdered your wife.'

The man did not inform anyone about the trip. Then how was the agent so sure that it was a murder?

Is the statement valid that it does not matter how much older a sibling is, eventually the younger one will be half as old as the older one?

John was so frustrated to be the suspect of being a sleeper terrorist that he shoot himself right between the eyes with a revolver in his toilet. The revolver and the bullets were accurate. Minutes later John walks out of the toilet unharmed.
How can this be possible?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

The following alphametic has only one solution. Can you find it?
ENLIST + SILENT + LISTEN = ANAGRAM

PS: You may start the number from 0.

Identify Me

Hint1: I am a god
Hint 2: I am a planet
Hint 3: measurer of heat