CBSE Class 10 Science 2023 · Paper 31/1/3 · Question 34

(a)(i) Testis: forms the male germ cells (sperms) and secretes the hormone testosterone, which regulates the formation of sperms and brings about the changes seen in boys at puberty. (ii) Scrotum: holds the testes outside the abdominal cavity, because sperm formation requires a temperature lower than the normal body temperature. (iii) Vas deferens: delivers the sperms from the testis; it unites with the tube from the urinary bladder, so the urethra is a common passage for sperms and urine. (iv) Seminal vesicle: adds its secretion (with that of the prostate gland) to the sperms; this fluid makes their transport easier and provides nutrition. (b) The placenta is a special tissue, a disc embedded in the uterine wall, that connects the embryo to the mother. It has villi on the embryo's side surrounded by blood spaces on the mother's side, giving a large surface area through which glucose and oxygen pass from the mother's blood to the embryo, and through which the embryo's wastes pass into the mother's blood to be removed.