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

What Word am I Looking For ?

You walk into a room where there are three primates held in their respective cages:
1) A lion who is eating the flesh of a goat.
2) An orangutan who is playing with blocks.
3) A donkey who is sitting idle.

Who is the most intelligent primate in the room?

Why do Chinese men eat more rice than Japanese men do ?

Can you place six X (crosses) in below board without making three in a row in any way ?

Using Only Five 5's and any mathematical operator make sum as 37

Solve the equation in the image by looking at the pattern closely.

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

Eight of us go fourth, not back, to protect our king from an attack. What are we?

I am a mother. However, I never give birth.

I am a father. However, I never nurse my children.

Wandering is not possible for me, but standing still happens occurs rarely.

Who am I?

One fine day, an intellectual man came to the emperor's court with the aim of testing Birbal's wittiness. In order to do this, he challenged Birbal to answer his question and hence prove that he was as intelligent and witty as he was said to be.
He asked Birbal, Do you want me to ask one difficult question or a hundred easy ones?
Since both Akbar and Birbal had had a tough day and were eager to leave, Birbal hastily told the intellectual to ask him a single difficult question.
Intellectual: OK. Tell me what came first into the world, the egg or the chicken?
Of course, the chicken, Birbal replied with a smile.
This time with a note of victory in his voice, the intellectual asked Birbal, How will you demonstrate that?
What did Birbal say?