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: Anatomy
In which of the following microvilli are not present? 
Select and explain. 
A. Gallbladder, B. Duodenum, C. Collecting duct, D. Proximal convoluted tubule
C: Collecting duct
Answer: C: Collecting duct 
Explanation: Ans: C. Collecting duct Microvilli - Finger-like cell surface extensions.Usually 0.1 mm in diameter & up to 2 mm long.Absorptive surfaces of epithelial enterocytes of small intestine - Arranged in regular parallel series & constitute striated border.In gallbladder epithelium & proximal kidney tubules - Are less regular constitute "brush border".