This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Out of the four layers, which cells of are the most active for protein synthesis: 
Select and explain. 
A. Spinous cell., B. Basal cell., C. Granular cell., D. Corneum cell.
A: Spinous cell.
Answer: A: Spinous cell. 
Explanation: The spinous (prickle) cells resemble a cocklebur or sticker that has each spine ending at a desmosome. Of the four layers, the spinous cells are the most active in protein synthesis. These cells synthesize additional proteins that differ from those made in the basal cells.