CBSE Class 10 Science 2017 · Paper 31/1 · Question 20

(a) (i) Ovary: produces the female germ cells, the eggs (one egg is produced every month by one of the ovaries), and female hormones. (ii) Uterus: the embryo is implanted in its thickened lining and develops there, nourished through the placenta, until birth; the rhythmic contraction of its muscles pushes the baby out at birth. (iii) Fallopian tube: carries the egg from the ovary towards the uterus; fertilisation takes place in it. (b) Structure: the placenta is a disc-shaped tissue embedded in the wall of the uterus. On the embryo's side it has finger-like villi, and on the mother's side blood spaces surround the villi, giving a large surface area. Functions: glucose (nutrition) and oxygen pass from the mother's blood to the embryo, and the waste substances of the embryo pass into the mother's blood to be removed.