The Mesozoic Era is often called the "Age of Reptiles," implying that mammals were insignificant during this time. However, the discovery of a fossilized mammal named Repenomamus in 130-million-year-old volcanic ash in China challenges this perception. The fossil preserves the remains of a young dinosaur inside the mammal's stomach. This finding implies that some Mesozoic mammals ______
Which choice most logically completes the text?
were strictly herbivores that only ate plants.
were large and aggressive enough to predate on dinosaurs.
evolved into dinosaurs over millions of years.
were exclusively scavengers that fed on already dead animals.
Correct Answer: B
Choice B is the best answer. The text challenges the view that mammals were insignificant. The evidence is a mammal fossil with a dinosaur inside its stomach. This directly implies that mammals were not just small prey, but were capable of predation on dinosaurs.
Choice A is incorrect because the fossil proves the mammal ate a dinosaur (meat), so it was not a strict herbivore. Choice C is incorrect because mammals and dinosaurs are distinct lineages; mammals did not evolve into dinosaurs. Choice D is incorrect because finding stomach contents suggests consumption, but "exclusively scavengers" is too strong a claim based on one fossil; predation is a more logical inference for a "challenge" to the "insignificant" status.