This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Transpo Processes, Subject name: Physiology
Which of the following is NOT a characteristic of facilitated diffusion? 
Select and explain. 
A. Inhibition, B. Saturability, C. Specificity, D. Uphill transpo
D: Uphill transpo
Answer: D: Uphill transpo 
Explanation: Facilitated diffusion is a carrier-mediated transpo. Carrier can get saturated as the concentration of the transpo molecule reach the "transpo maximum". Carrier can be inhibited by specific ligands (or poisons). Also, carrier exhibits specificity. Substance will be transpoed from high to low concentration - the downhill transpo.