Answer: D) Heat transfer by molecules colliding with adjacent molecules.
Step-by-step explanation:
The heat transfer is achieved by three modes:
a. Conduction: This type of heat transfer happens when there is direct contact between two objects. In conduction, heat is transferred by molecules bumping into each other.
b. Convection: This type of heat transfer happens when there is a movement of fluid (liquid or gas).
The hot liquid rises up due to its low density and the cold liquid sinks thus generating convection currents.
c. Radiation: This type of heat transfer happens when there is direct transfer of electromagnetic energy through space.