Unlike modern animal scientists, dinosaur scientists cannot sit on a hillside and use telescopes to watch dinosaurs in order to know how they lived and whether they were good parents. Instead, they have to search hard for information from dinosaurs' fossils   because dinosaurs died out millions of years ago. It's very difficult for the scientists to reach an agreement because different results can be got from the same fossils. Many fossils of the same kind of dinosaurs have been dug out from one place. They might have formed when an entire group of dinosaurs got stuck   all at once, or they might have been the result of dinosaurs getting stuck one after another over a course of a few centuries. Thus we can say that dinosaurs might have in the first case lived in big groups and in the second lived alone. Though there are two different results, dinosaur scientists now generally agree that at least some kinds of dinosaurs lived in big groups. "That's pretty much settled at this point," says Paul Sereno. A kind of dinosaurs called Sauropods left behind tracks in the western United States that appear to run north and south, suggesting that they even moved long distances together. As to whether dinosaurs cared for their young, dinosaur scientists have turned to the closest living relatives of dinosaurs-birds and crocodiles-for possible models. Birds give a lot of care to their young, while crocodiles just help their young to the water. The discovered fossils of dinosaurs sitting on their eggs and staying with their young suggest the parents were taking care of their babies, but we still cannot say that all dinosaurs did the same. There is still a long way to go before the above questions could be answered. Dinosaur scientists, will have to find more proof to reach an agreement. Dinosaur scientists can get information directly by  _  .
studying dinosaur fossils examining modern animals watching dinosaurs using telescopes
Question: Unlike modern animal scientists, dinosaur scientists cannot sit on a hillside and use telescopes to watch dinosaurs in order to know how they lived and whether they were good parents. Instead, they have to search hard for information from dinosaurs' fossils   because dinosaurs died out millions of years ago. It's very difficult for the scientists to reach an agreement because different results can be got from the same fossils. Many fossils of the same kind of dinosaurs have been dug out from one place. They might have formed when an entire group of dinosaurs got stuck   all at once, or they might have been the result of dinosaurs getting stuck one after another over a course of a few centuries. Thus we can say that dinosaurs might have in the first case lived in big groups and in the second lived alone. Though there are two different results, dinosaur scientists now generally agree that at least some kinds of dinosaurs lived in big groups. "That's pretty much settled at this point," says Paul Sereno. A kind of dinosaurs called Sauropods left behind tracks in the western United States that appear to run north and south, suggesting that they even moved long distances together. As to whether dinosaurs cared for their young, dinosaur scientists have turned to the closest living relatives of dinosaurs-birds and crocodiles-for possible models. Birds give a lot of care to their young, while crocodiles just help their young to the water. The discovered fossils of dinosaurs sitting on their eggs and staying with their young suggest the parents were taking care of their babies, but we still cannot say that all dinosaurs did the same. There is still a long way to go before the above questions could be answered. Dinosaur scientists, will have to find more proof to reach an agreement. Dinosaur scientists can get information directly by  _  .
A. studying dinosaur fossils
B. examining modern animals
C. watching dinosaurs
D. using telescopes
Answer: