(1) A modern dentist would certainly enjoy having a hadrosaur as a client. (2) What a lot of business it would bring! (3) Though an adult human being has only 32 teeth, this duck-billed dinosaur of the Late Cretaceous Period had about 2,000 teeth, with 500 along each side of each jaw. (4) Unlike human beings, who grow two sets of teeth in their lifetimes, the hadrosaurs, like sharks and modern reptiles, had built-in replacement teeth. (5) In skeletal remains of the jaws of these toothy beasts, scientists have found entire banks of replacement teeth. (6) These stand-ins rested in a bed of cartilage, ready to substitute for teeth that became worn down or broke off—like having a built-in dentist! (7) That is a good thing because microwear studies of hadrosaur teeth have revealed tiny cracks and chips, leading some scientists to believe that the dinosaurs ate tough plants that damaged teeth. The following question has two parts. Answer Part A first, and then Part B.

Part A
Which choice best describes the author’s purpose in this passage?

A. to persuade readers to like hadrosaurs instead of fearing them
B. to share information about hadrosaurs in an entertaining way
C. to describe the lifecycle of hadrosaurs
D. to explain why hadrosaurs had damaged teeth
Part B
Click on the highlighted quotation in the passage that most clearly illustrates the answer to Part A.
(1) A modern dentist would certainly enjoy having a hadrosaur as a client. (2) What a lot of business it would bring! (3) Though an adult human being has only 32 teeth, this duck-billed dinosaur of the Late Cretaceous Period had about 2,000 teeth, with 500 along each side of each jaw. (4) Unlike human beings, who grow two sets of teeth in their lifetimes, the hadrosaurs, like sharks and modern reptiles, had built-in replacement teeth. (5) In skeletal remains of the jaws of these toothy beasts, scientists have found entire banks of replacement teeth. (6) These stand-ins rested in a bed of cartilage, ready to substitute for teeth that became worn down or broke off—like having a built-in dentist! (7) That is a good thing because microwear studies of hadrosaur teeth have revealed tiny cracks and chips, leading some scientists to believe that the dinosaurs ate tough plants that damaged teeth.