Write the function of each of the following: (a) Middle piece in human sperm. (b) Tapetum in anthers. (c) Luteinizing hormone in human males.

(a) The middle piece of human sperm possesses numerous mitochondria, which produces energy for the movement of the tail that facilitate sperm motility essential for fertilization (b) Microsporangium is surrounded by 4 wall layers as epidermis, endothecium, middle layer and tapetum. Outer 3 wall layers performs the function of protection and help in dehiscence of anther to release the pollen. The innermost wall layer is the tapetum, it nourishes the developing pollen grains (c) Luteinizing hormone acts at the Leydig cells and stimulates the synthesis and secretion of androgens.