Evaluate the effectiveness of the sodium-glucose symporter in transporting glucose into intestinal epithelial cells.

• A. The sodium-glucose symporter is ineffective because it moves both sodium and glucose down their concentration gradients.
• B. The sodium-glucose symporter effectively transports glucose by using the sodium gradient to move glucose against its concentration gradient.
• C. The sodium-glucose symporter passively transports glucose down its concentration gradient.
• D. The sodium-glucose symporter is ineffective because it requires ATP to transport glucose.

Answer: (B)