Pregnant Plesiosaur Fossil May Shed Light on Ancient Animal’s Behavior by PBS NewsHour Scientists have pieced together the first-ever fossil of a pregnant plesiosaur, a giant Mesozoic sea reptile from the Cretaceous Era, with an embryo still inside. The animal, which roamed the seas 78-million years ago, is about 15-feet long—the length of a minibus—and bones indicate that the baby plesiosaur would have been as long as six feet when born. The finding, published in the online edition of the journal Science on Thursday, is definitive evidence that the giant sea creature gave birth to single, live offspring, rather than laying eggs, like most reptiles, says paleontologist and lead author F. Robin O’Keefe. This reproductive behavior also indicates that the animals were gregarious social creatures that cared for their young, similar to toothed whales or dolphins, according to the paper. © NewsHour Productions LLC. All Rights Reserved. Question Use the passage “Pregnant Plesiosaur Fossil May Shed Light on Ancient Animal’s Behavior” to answer the question. Which detail should be included in a summary of the passage? (1 point) Responses The fossil scientists discovered is about the length of a minibus. The fossil scientists discovered is about the length of a minibus. Most reptiles lay eggs, but the plesiosaur carried a live baby. Most reptiles lay eggs, but the plesiosaur carried a live baby. The lead author of the study, F. Robin O’Keefe, is a paleontologist. The lead author of the study, F. Robin O’Keefe, is a paleontologist. Dolphins and whales have similar social behaviors.

Answer 1

A good detail to include in a summary of the passage is: Most reptiles lay eggs, but the plesiosaur carried a live baby. This detail captures the main finding of the research regarding the reproductive behavior of the plesiosaur, which is central to the passage.