Which of the following is also called Marsh Gas?  

The ozone layer in the atmosphere is at a height of about

Which one among the following nontoxic gases helps in formation of enzymes which ripen fruit?

A monkey sitting on a branch of a tree suddenly falling down towards the ground in an example of___.

The most abundant element in the human body is 

If the radius of a person's blood vessels decreases, what will be the effect on his blood pressure?

The level of sound during normal conversation is

By - the product obtained by the soap industry is