Answer:
B. A large number of atoms move from one place to another
Explanation:
Convection is heat transfer by the movement of atoms of a substance from one region to another across a temperature gradient. Since atoms of solids are rigidly held in place, convection only occurs in liquids and gases since they flow.
Convection occurs when the temperature of one region of a fluid (liquid or gas) is higher than its other region. There is thus a mass movement of atoms from one region to the other due to a temperature difference. The atoms will continue to move to the region of lower temperature until the temperature of both regions are the same at an equilibrium temperature.
