Question

why does colder air sink and warmer air rise, creating convection currents in the atmosphere?
a. cold air is less dense than warm air.
b. cold air is denser than warm air.
c. warm air is denser than cold air.
d. air curves to the right in the northern hemisphere.

Explanation:

Density determines whether air sinks or rises. Cold air has more mass per unit volume (higher density) than warm air. According to the principle of buoyancy, denser (colder) air will sink below less - dense (warmer) air. Option A is incorrect as cold air is denser, not less dense. Option C is wrong because warm air is less dense. Option D is about the Coriolis effect (air curving in the Northern Hemisphere) which is not related to the density - based sinking/r rising of air.

Answer:

B. Cold air is denser than warm air.