Question

Which among the following has an opposable thumb?
A. Platypus
B. Kangaroo
C. Mole
D. Lemur

Answer 1

Hint: The opposable thumb is a characteristic of Primate. It allows the digits to handle and grasp objects. A primate is the order of the class Mammalia that includes any mammal of the group that includes lemurs, lorises, tarsiers, monkeys, apes, and humans. The order Primates, is the third most diverse order of mammals, with 300 or more species.

Complete answer:
Primate is any mammal of the group that includes the tarsiers, monkeys, apes, lemurs, lorises, and humans.
The presence of an opposable thumb is a characteristic feature of Primates. A thumb that is located opposite of the rest of the fingers is called an opposable thumb. It helps them hold objects and establish strong grips. The opposable thumb has helped the human species in various ways such as to develop more accurate fine motor skills. It is also believed that not just in humans or their evolutionary ancestors, but other primates as well, the opposable thumb has directly led to the development of tools.
Lemurs are Primates hence have an opposable thumb. Their sense of smell is more. Their eyes seem to be adapted for nocturnal life, although some species are at times active during the day. All lemurs are characterized by a reflective layer, tapetum, a noninvasive (epitheliochorial) placenta; and a claw on the second toe of the foot.
Kangaroos belong to the order Diprotodontia, do not, however, have opposable thumbs, but they do have long claws, differentiating themselves from the hands of primates.
Moles belong to the order Eulipotyphla.
Platypus belongs to the order Monotremata, hence not a primate.
So, the correct answer is “Option D”.

Note:
Lemurs are mammals of the order Primates. Since Lemur is the only primate among the options so it has an opposable thumb as it helps them hold objects and establish strong grips. Lemurs have opposable thumbs as well as opposable big toes.