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: Physiology
How many layers are present in cerebral coex? 
Select and explain. 
A. 5, B. 6, C. 3, D. 4
B: 6
Answer: B: 6 
Explanation: Composed of 6 layers. LAYERS OF CEREBRAL COEX: Composed of 6 layers - Layer/Lamina I - "Molecular layer" Contains nerve fibers. Mainly dendrites of pyramidal cells & axons of granular cells. Layer/Lamina II - "External granule cell layer" Contains mainly granule cells. Layer/Lamina III - "External pyramidal cell layer" Contains mainly small to medium size pyramidal cells Some granular cells also present Layer/Lamina IV - "Internal granule cell layer" Contains predominately granule cells & nerve fibers. Specific sensory input through thalamocoical fibers terminate primarily in coical layer IV on stellate (granule cells). Diffuse non-specific sensory afferents are distributed through layer I-IV. Layer/Lamina V - "Internal pyramidal cell layer" Contains large pyramidal cells. Descending tracts, i.e. projection fibers from coex (coicospinal tract, coicobulbar tract) are the axons of these pyramidal cells of Layer V Layer/Lamina VI - "Multiform layer" Contains all types of cells