Primate females:

a. give birth to more offspring than do many other mammals

b. give birth to twins regularly

c. invest less in their offspring than do many other mammals

d. give birth to fewer offspring than do many other mammals

Primate females give birth to fewer offspring than do many other mammals. Many other mammals give birth to full litters, sometimes as many as 20 at a time, where primates typically give birth to between one and two offspring at a time, and rarely to three, without medical intervention. Mammals tend to give birth to fewer offspring than they have teats/nipples to allow for feeding.