12. Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?
No, the number of eggs produced in oviparous animals and young ones in viviparous animals are not equal. It is because oviparous animals lay eggs outside the body of female in water, land etc so these eggs do not get the conditions that are necessary for the development and hatching of the eggs. Thus, due to the lack of parental care out of the total eggs produced the chances of survival are very low. To compensate for this loss many eggs are produced. On the other hand, the embryos of viviparous animals are inside the body of a female and they get proper nourishment and conditions necessary for their growth and development. Even after they are born, they are provided with parental care. So, the chances of survival are high and only a few young ones could be supported.