Question

why do african wildcats purr but leopards roar? researchers hypothesize that this difference between the two feline species may be partly due to a u - shaped bone in their throats called the hyoid. african wildcats, which are much smaller than leopards, have a rigid hyoid that rumbles when the cats larynx vibrates, resulting in a purr. by contrast, leopards have a somewhat flexible hyoid, and the bone is attached to the skull with a stretchy ligament that african wildcats lack. these traits allow leopards and most other species of big cats to produce powerful roars. the same traits may also prevent most big cats from purring.
which choice best describes the overall structure of the text?
the text compares the habitats of two species, then explains how those habitats are changing.
the text poses a question about two species, then presents a possible answer.
the text presents a theory about two species, then discusses facts that weaken it.
the text describes a behavior shared by two species, then discusses other behaviors shared by them.

Explanation:

The text begins with a question ("Why do African wildcats purr but leopards roar?") and then presents a possible answer (the difference in the hyoid bone structure).

Answer:

B. The text poses a question about two species, then presents a possible answer.