Match the Column 1 with Column 2 :

A-iv,B-i,C-ii,D-iii

The correct answer is Option (4) - A-iv,B-i,C-ii,D-iii

A. Spermatogenesis starts at the age of puberty due to significant increase in the secretion of gonadotropin releasing hormone (GnRH). This is a hypothalamic hormone. The increased levels of GnRH then acts at the anterior pituitary gland and stimulates secretion of two gonadotropins – luteinising hormone (LH) and follicle stimulating hormone (FSH).

B. The acrosome is a cap-like structure located at the tip of the sperm's head. It contains enzymes that play a critical role in helping the sperm penetrate the protective layers of the egg (ovum) during the fertilization process. The acrosome's enzymatic action is necessary for the successful fusion of the sperm with the egg.

C. Both hCG and hPL are hormones produced by the placenta during pregnancy.Placenta also acts as an endocrine tissue and produces several hormones like human chorionic gonadotropin (hCG), human placental lactogen (hPL), estrogen etc.

D. The regions outside the seminiferous tubules called as interstitial spaces, contain small blood vessels and interstitial cells or Leydig cells. LH acts at the Leydig cells and stimulates synthesis and secretion of androgens. Androgens, in turn, stimulate the process of spermatogenesis. Leydig cells synthesise and secrete testicular hormones, called as androgens. Other immunologically competent cells are also present.