The study of primates is interesting for many reasons, including the fact that only primates have opposable thumbs. The lemurs are lower primates and the only primates indigenous to Madagascar, a large island off the coast of southeastern Africa. Some species of lemurs are the only living lower primates that are diurnal, that is, active primarily during the day. All higher primates are thought to have evolved from a single diurnal species of lower primates.
Which one of the following can be properly inferred from the information above?The passage says lemurs are the only primates indigenous to Madagascar, and lemurs are lower primates.
So any primate indigenous to Madagascar must be a lemur, and therefore must be a lower primate, not a
higher primate.
(A) The chimpanzee, a higher primate, evolved from the lemur.
This is not supported. Higher primates evolved from a single diurnal species of lower primates, but the passage does not say that species was a lemur.
(B) No primates indigenous to Madagascar are diurnal higher primates.
This is correct. The only primates indigenous to Madagascar are lemurs, and lemurs are lower primates. So there cannot be any indigenous higher primates in Madagascar, diurnal or otherwise.
(C) No higher primate is nocturnal.
This is not supported. Higher primates evolved from a diurnal lower primate, but that does not prove all higher primates are diurnal now.
(D) There are some lemurs without opposable thumbs.
This is not supported. The passage gives no basis for saying some lemurs lack opposable thumbs.
(E) There are no nocturnal lemurs.
This is incorrect. The passage says some lemur species are diurnal. That does not mean all lemurs are diurnal.
Answer: (B)