Question

As water cools it becomes more dense. As water reached the surface of the tank

it became cooler and began to sink. As the water sank, it heated again and moved
upward again.
The plant cycled around the tank with the moving water. This cycling of cool and
warm temperatures is an example of
A. convection.
B. conduction.
C. expansion.
D. radiation.

Answer 1

The cycling of cool and warm temperatures in the water tank, where the cooler water sinks and the warmer water rises, is an example of convection. So, the correct answer is A. convection.