Why does cool material sink in Convectional Current Theory?

Correct answer: Its density increases on cooling

In a convection current, material generally contracts as it cools. Its mass remains nearly unchanged, but its volume decreases, so its density increases. The cooler, denser material sinks relative to the surrounding warmer, less dense material. Option B is incorrect because cooling alone does not increase mass. Exam tip: in convection, warm, less dense material rises, while cool, denser material sinks.