Nhận biết (M1)

Why do ocelots purr but jaguars roar? Researchers hypothesize that this difference between the two feline species may be partly due to a U-shaped bone in their throats. This bone is called the hyoid. Ocelots, which are much smaller than jaguars, have a rigid hyoid that rumbles when the cat's larynx vibrates, resulting in a purr. By contrast, jaguars have a somewhat flexible hyoid, and the bone is attached to the skull with a stretchy ligament that ocelots lack. These traits allow jaguars and most other species of big cats to roar. The same traits may also prevent most big cats from purring.

Which choice best describes the function of the underlined sentence in the text as a whole?

• A.

  The sentence explains the unique nature of the researchers' hypothesis.

• B.

  The sentence identifies the location of a bone in felines.

• C.

  The sentence introduces a term that is used in the discussion that follows.

• D.

  The sentence summarizes the debate presented in the text.