[Campbell Biology P.793] According to the text, which statement accurately describes the opp... | Practice Question

According to the text, which statement accurately describes the opposable thumb in primates?

  • A: All living primates, including humans, have a fully opposable thumb used for precise manipulation.
  • B: Monkeys and apes use their opposable thumb for a grasping 'power grip,' while humans have a distinct bone structure enabling more precise manipulation.
  • C: The opposable thumb is unique to humans and allows for intricate tool use, distinguishing them from all other primates.
  • D: Primates have a thumb that is completely immobile and separate from the fingers, adapting them for tree-dwelling.

Explanation

The text explicitly states: 'All primates also have a thumb that is relatively movable and separate from the fingers, but monkeys and apes have a fully opposable thumb; that is, they can touch the ventral surface fingerprint side of the tip of all four fingers with the ventral surface of the thumb of the same hand. In monkeys and apes other than humans, the opposable thumb functions in a grasping 'power grip.' In humans, a distinctive bone structure at the base of the thumb allows it to be used for more precise manipulation.'