CBSE Class 10 Science 2017 · Paper 31(B)/C · Question 20

(a) (i) Ovary: produces the female gametes, the eggs (each month one egg is released by one of the ovaries), and secretes female hormones such as oestrogen. (ii) Uterus: the fertilised egg is implanted in its thickened, blood-rich lining, and the embryo develops there, nourished through the placenta, until birth; its muscles contract rhythmically to push the baby out at birth. (iii) Oviduct (fallopian tube): carries the egg from the ovary towards the uterus; fertilisation takes place in it. (b) The embryo is nourished through the placenta, a disc-like tissue embedded in the wall of the uterus. The placenta has villi on the embryo's side, surrounded by blood spaces on the mother's side, which give a large surface area. Glucose and oxygen pass from the mother's blood into the villi and reach the embryo through the umbilical cord, and the embryo's wastes pass into the mother's blood to be removed.