No one wants to have it, but if one got it, he does not want to lose it. What is It?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

Find the hidden tiger in the given optical illusion ?

Identify the 10 differences between the two given pictures.

What does below chemistry rebus means?

what one word does the below rebus identifies?

If two fifty-foot ropes are suspended from a forty-foot ceiling that is twenty feet apart, how much rope will you be able to steal if you have a knife?

How can one talk without saying a single word?

Can you figure out the logic I used to decide the order of the following words:
gun, shoe, spree, door, hive, kicks, heaven, gate, line, den

What you cannot hold but it is yours?