When fluids are heated from the bottom, convection currents are produced because

Options

A. Molecular motion of fluid becomes aligned
B. Molecular collisions take place within the fluid
C. Heated fluid becomes denser than the cold fluid above it
D. Heated fluid becomes less dense than the cold fluid above it

Answer

D

Explanation

Pressure = `rho g h because r_("bottom") lt rho_("top") therefore P_("top") gt P_("bottom")` .