Why do we fall ill ?

Why do we call density as a derived quantity?

Why do we call our heart myogenic ?

Why do we call our heart myogenic?

Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?

Why do we apply paint on iron articles?

Why do we add alum to purify water ?

If an electric fan be switched on in a closed room, will the air of the room be cooled? If not, why do we feel cold?

Why do we usually use isotopes emitting gamma radiations as radioactive tracers in medical science ? [Hint : gamma radiations are most penetrating]

Why do some children fall ill more frequently than others living in the same locality?

Why do we classify organisms?