plz answer fast i have exam tomorrow 

a. Hormone X is FSH (follicle-stimulating hormone) and Y is LH (luteinizing hormone).

b. Organ Z is ovary. During first phase of menstrual cycle i.e the follicular phase, egg cells present in ovaries are stimulated and gets matured in sac-like structure called follicle.

c. Luteinizing hormone (LH) secreted by the pituitary gland induces the rupture of graffian follicle and thereby the release of ovum called ovulation. It also helps in the development of corpus luteum. 
Progesterone acts on mammary glands and stimulates formation of alveoli-like structures storing milk and also help in Milk secretion.