Explanation

9. Choice B is the only correct answer.

Choice A is incorrect:

the passage mentions that fossilized footprints permit the inference that sauropods exhibited herd behavior, but there is no indication that this or any other social behavior can be inferred from sauropod teeth.

Choice B is correct:

the passage states that sauropods were herbivorous (feeding on plants) and that “the shape of sauropod teeth suggested what they ate.”

Choice C is incorrect:

the passage says that there are no modern land animals similar in size to sauropods, not that there are no such animals with similar teeth.


10. Choice A is the only correct answer.

Choice A is correct:

the last sentence of the passage implies that the discovery of fossilized sauropod nesting grounds resolved the question of whether sauropods laid eggs or gave birth to live young and therefore provided evidence of sauropods’ reproductive behavior. Until this discovery, except for the trackways that showed herd behavior, “fossils incorporating direct evidence” of sauropod behavior were “almost nonexistent”.

Choice B is incorrect:

according to the passage, trackways provided evidence of herd behavior, whereas fossilized nesting grounds provided evidence concerning reproductive behavior. There is no information in the passage to suggest that the nesting grounds confirmed evidence provided by the trackways, or even that the trackway evidence needed confirming.

Choice C is incorrect:

the passage presents fossilized nesting grounds as providing evidence about reproductive behavior, not herd behavior. Nothing in the passage suggests that there are theories of the nature of sauropod herd behavior that have been reevaluated.