Question

what happens in a convection cell? cold, dense material moves horizontally, while hot, less dense material moves vertically. hot, less dense material moves horizontally, while cold, dense material moves vertically. cold, dense material sinks while hot, less dense material rises. hot, less dense material rises and cold dense material also rises.

Explanation:

In a convection cell, the principle is based on density differences. Hot material has lower density (due to increased molecular spacing as it heats up) and thus rises. Cold material is denser (molecules are closer together) and sinks. This creates a circular - like motion (the convection cell). The first two options are incorrect because both hot and cold materials move both vertically and horizontally in a convection cell (as part of the circular motion). The fourth option is wrong because cold, dense material does not rise.

Answer:

Cold, dense material sinks while hot, less dense material rises.