Final answer:
The answer to the student's question is 'C. Does not, channel proteins(or carrier proteins)'. Facilitated diffusion is a type of passive transport that moves substances across cell membranes without energy but with the help of specific proteins.
Step-by-step explanation:
Facilitated diffusion does not require energy but it does require the help of channel proteins or carrier proteins. The correct answer to the student's question is 'C. Does not, channel proteins(or carrier proteins)'. In facilitated diffusion, substances move across the cell membrane down their concentration gradient through specific protein channels in the membrane. This process of passive transport allows molecules that cannot readily diffuse through the membrane to be transported with the assistance of channel proteins, which are like pores, and carrier proteins, which change shape to move the molecules across. Unlike active transport, which requires energy typically in the form of ATP to move substances against their concentration gradient, facilitated diffusion is an energy-independent process.