When pollen grains are suspended in water and viewed through a microscope, they appear to be in a state of constant but erratic motion. This is due to?

A.

convection currents

B.

small changes

C.

small changes in temperature

D.

a chemical reaction between the pollen grain and water

E.

the bombardment of the pollen grains by molecules of water

Correct answer is E

No explanation has been provided for this answer.