In electric ovens, the heat in the oven comes from the bottom when you bake something. However, cookies baking on the top shelf get done before cookies on the bottom shelf even though the bottom shelf is closer to the heat source. Why does this happen? A. The oven heats the air at the bottom, causing it to become less dense and rise. The hotter air stays at the top of the oven and transfers more energy to the cookies, cooking them faster.

B. The oven heats the cookies on the bottom first and then transfers the heat from the bottom cookies to the top, stealing their thermal energy.

C. The cookies on the top get cooked faster because you usually put them on the top shelf first.