Questions 1 and 4 are based on this passage

The main exception to primate researchers’ general pattern has been the study of male care among monogamous primates. It has been known for over 200 years, ever since a zoologist- illustrator named George Edwards decided to watch the behavior of pet marmosets in a London garden, that among certain species of New World monkeys males contributed direct care for infants that equaled or exceeded that given by females. Mothers among marmosets and tamarins typically give birth to twins, as often as twice a year, and to court the female in her staggering reproductive burden the male carries the infant at all times except when the mother is actually suckling it. It was assumed by Kleiman that monogamy and male confidence of paternity were essential to the evolution of such care, and at the same time, it was assumed by Symons and others that monogamy among primates must be fairly rare.

Recent findings, however, make it necessary to reverse this picture. First of all, monogamy among primates turns out to be rather more frequent than previously believed (either obligate or facultive monogamy can be documented for some 17-20 percent of extant primates) and second, male care turns out to be far more extensive than previously thought and not necessarily confined to monogamous species, according to Hrdy. Whereas previously, it was assumed that monogamy and male certainty of paternity facilitated the evolution of male care, it now seems appropriate to consider the alternative possibility that the extraordinary capacity of male primates to look out for the fates of infants did in some way pre-adapt members of this order for the sort of close, long-term relationships between males and females that, under some ecological circumstances, leads to monogamy. Either scenario could be true. The point is that on the basis of present knowledge there is no reason to view male care as a restricted or specialized phenomenon. In sum, though it remains true that mothers among virtually all primates devote more time and/ or energy to rearing infants than do males, males nonetheless play a more varied and critical role in infant survival than is generally realized.