站立时窦腔内分泌物最不容易流出的鼻旁窦是： A: frontal sinus B: maxillary sinus C: sphenoidal sinus D: anterior group of the ethmoidal sinuses E: posterior group of the ethmoidal sinuses

The preferential site of the B cells in the spleen is the() A: sinusoids B: subcapsular sinuses C: trabecula D: white pulp nodules E: periarterial lymphatic sheath

Which of the following is true statement relating to the meninges? A: The dura mater is composed of a dense fibrous connective tissue. B: The dura mater around the brain is single-layered. C: Venous sinuses occur between the two dural layers around the spinal cord. D: The most superficial meninx is the arachnoid membrane.