Question: What do you think would have happened if humans also gave birth to a large number of babies at the same time?
Answer: Since mortality of infants is very low as compared to animals. Therefore if they gave birth to a large number of babies at the same time, their population would have become very high and unsustainable.
Question: Can a woman with a blocked fallopian tube give birth to a child? Why?
Answer: No, a blocked fallopian tube prevents the ova to fertilize with sperm cell as the male gametes from the father cannot come in contact with female gametes of mother.
Question: Under what circumstances can twins are born in humans?
Answer: When two ova can be produced by ovaries and both get fertilized, it can result in twins.
Question: Why is it that dogs always produce several puppies whereas human beings usually produce only one child at a time?
Answer: Dogs produce more than one egg at a time. Hence, more puppies are born to them at the same time. Whereas humans usually produce one egg at a time, hence produce only one child at a time.
Very nice website!
Best website for NCERT Notes.