Which of the following uses protein channels to carry large molecules and ions across the membrane without energy?

Simple Diffusion Across the Cell (Plasma) Membrane: The structure of the lipid bilayer allows small, uncharged substances such as oxygen and carbon dioxide, and hydrophobic molecules such as lipids, to pass through the cell membrane, down their concentration gradient, by simple diffusion.

Explanation: Large molecules like glucose or carbohydrates use proteins to help move across cell membranes. Some of the membrane proteins have carbohydrate Chains attached to help cells in recognize each other and certain molecules

did this help

just finished the test, the answer is d, greg is the least cost-effective because he charges the most for the project