Why does old car bumper change colour?

When a piece of ice is placed in water at room temperatur, ice melts and water cools down. Why does their temperture change?

When does urine appear deeply coloured?

Why does a rubber band become loose after repeated use?

Answer the following : Why does car uses a battery instead of a cell ?

Which pigment causes the skin colour ? Can we change the skin colour ?

Animal that can change its colour is

Why do meteorogical models need to be changed continually?

Why do diurnal changes occur in osmotic potential of guard cells?

Identify me: I am a clever molluscan, I can change my colour.

Why doensn't the stone move up all the time? Why does it fall down after reaching a certain height?