Q4. What is expelled from the uterus soon after the infant is delivered?
The placenta (NCERT page 38).
Q5. Assertion: an injection of oxytocin can be used to induce delivery. Reason: oxytocin acts on the uterine muscle and causes stronger uterine contractions. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion (reasoned from NCERT page 38, where NCERT asks what doctors inject to induce delivery and describes oxytocin’s action on the uterine muscle).
Q6. When do the mammary glands differentiate and when do they start producing milk?
They differentiate during pregnancy and start producing milk towards the end of pregnancy (NCERT page 38).