Tour of the electromagnetic spectrum webquest

your answer is "the 1950's"

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.