Can you name an animal whose killing cannot be performed without spilling your own blood?

Fate has decided that you will only be pleased to meet me when you need me

Maybe that is why, when I am working, I start working

However annoying I may be to the regulars, the little ones are always inspired

I will always be waiting if you try to reach me

How many of you can guess my name, let me see

Twice ten are six of us,

Six are but three of us,

Nine are but four of us;

What can we possibly be?

Would you know more of us?

Twelve are but six of us,

Five are but four, do you see?

What are we?

Why Aeroplane windows are round?

How many minutes are there in Feb 2017?

Note: The shortest answer is the correct answer.

There are 4 big houses. They are made from the materials: red marble, green marble, white marble and blue marble.

* Mrs Jennifer's house is somewhere to the left of the green marble one and the third one alone is white marble.
* Mrs Sharon owns a red marbles house and Mr Cruz does not live at either end, but lives somewhere to the right of the blue marbles house.
* Mr Danny lives in the fourth house, while the first house is not made from red marble.

Who lives where, and what is their house made from?

A man dies of old age on his 25 birthday. How is this possible?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

Manish and Manoj play 5 games of chess.
Both Manish and Manoj win the exact same number of games. There is no tie at all.

How?

Which word is least like the others? Third, fourth, fifth, sixth, seventh, eighth, ninth?