CBSE Class 10 Science 2020 · Paper 31/5/3 · Question 27(a)

(a) Any two of these: to prevent unwanted pregnancies, so that the couple decides when to have a child and how many children to have; to keep a gap between children, so that the mother's health is not harmed by frequent pregnancies; to prevent sexually transmitted diseases, by using barrier methods such as the condom. (b) The processes in order: 1. Ovary: an egg is produced (matures) and is released, one egg each month. 2. Oviduct (fallopian tube): the egg is carried from the ovary into the oviduct. 3. Oviduct: sperms reach the egg and fertilisation takes place, forming the zygote. 4. Uterus: the zygote divides to form an embryo, which is implanted in the thick lining of the uterus. 5. Uterus: the embryo, nourished through the placenta, grows and develops into a foetus. 6. Uterus, cervix and vagina: after about nine months the uterine muscles contract rhythmically and the baby is delivered through the vagina (childbirth).