the T. rex's fossil leg bone still have actual tissue

The material discusses that leg bone of the T. rex's fossil still has remains of actual tissues of the animal. While the reading looks at the topic from one perspective, the listening challenges certain points outlined in the reading passage. First, the reading claims that the leg bone of the T. rex's fossils have branching channels that seemed to be hollows where the blood vessels were located. On the other hand, the listening opposed this and says that a died bacteria that lived inside the fossil could colonize hollows like channels. Furthermore, the professor mentions that bacteria lived inside the fossil could leave organic material. As a result, these hollows might not for blood vessels, but they are just traces or residue left by bacteria. Second, the author posits that when they examined the inner bone by microscope they found spheres that could be blood cells. On the contrary, the lecturer refutes this and states that a fossil fo a primitive animal had the same spheres; however, they did not have blood cells. Moreover, the professor claims that these spheres could be a different organism called reddish marrow. third, the author mentions that the dinosaur's leg bone contains collagen. Conversely, the lecturer contradicts this and says that collagen could not last longer than a hundred thousand years, nevertheless, the fossil remained for seventy million years. In addition to that, the professor states that collagen could not stay that long, so the collagen may come from human skin of researchers who handling this fossil.