I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

I am green and found in the forest and have needles instead of leaves. What am I?
Hint 1: It can be used for Christmas decorations.
Hint 2: I have a strong, scent that is used in air fresheners.

A man plots the murder of his wife. His plan is full proof. Nobody saw them leaving their house. He stabbed her with a knife while driving. She died on the spot. He threw her body in a valley. He threw the knife carefully wiping his finger prints on a random garbage bin. Then he went back to his home and no one was watching him this time as well.

After an hour, he was called by the local police department who informed him that his wife was murdered. They asked him to reach the scene of crime immediately. But as soon as he arrived at the crime scene, he was arrested by them.

How did the police know that he himself is the murderer?

What can jump higher than a building?

I am quite hot but become too cold if you remove the first two letters. What am I?

What is the Surname of Barbie Doll?

In this image, you can see three almost identical Doraemon images. Can you spot the odd one out from them?

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

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