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
Among all the layers of the scalp which layer is highly vascular? 
Select and explain. 
A. Skin, B. Subcutaneous tissue, C. Aponeurosis, D. Loose connective tissue
B: Subcutaneous tissue
Answer: B: Subcutaneous tissue 
Explanation: Scalp consists of the overlying soft tissues as well as underlying calvarium. The soft tissues composing the scalp are skin, connective tissue (subcutaneous), aponeurosis (galea aponeurotica), loose areolar connective tissue, and pericranium. The connective tissue layer (subcutaneous) contains the vast majority of the vasculature and nerve supply of the scalp. This layer is laced with strong fibrous reticula that hold the vessels open when the scalp is cut, causing profuse bleeding. The external carotid aery and internal carotid aery provides vessels to the scalp, with extensive anastomoses.