Animal fossils usually provide very little opportunity to study the actual animal tissues because in fossils the animals living tissues have been largely replaced by minerals Thus scientists were very excited recently when it appeared that a 70 millio

The reading and the lecture are both about the existence of the remains of the T. rex's actual tissues on its discovered fossils. While the author of the reading argues that there are some materials inside the T. rex's leg bone that seem to be remnants of the animal tissues such as blood vessels, red blood cells, and collagen, the professor disputes this claim. He states that he is skeptical about the whole idea. The lecturer casts doubt on the main points made in the reading passage by providing three controversial reasons.

In the reading, the writer begins by saying that the bone contains some small holes, which are probably the location of blood vessels. Also, these hollow parts include soft and flexible organic substances, which are the indicator of the blood vessels of T. rex. However, the professor disagrees with this idea. He asserts that this soft substance has nothing to do with the blood vessels and it is the result of something else. He claims that it is more probable that the bacteria colonized these hollow parts and they left behind this soft and organic material.

Furthermore, according to the reading microscopic examinations of the different parts of that bone shows the existence of spheres that are the size of the red blood cells, and they could be the remains of red blood cells. On the other hand, the professor points out that scientists have found these spheres in the fossils of other animals in that region; even the primitive animals, which did not have red blood cells. He believes that these spheres originated from a different source, maybe another reddish material.

Finally, the author believes that the discovered bone contains collagen that belongs to T. rex. Not surprisingly, the lecturer refutes this assertion by contending that collagen can not last more than one hundred thousand years. He says that this collagen may come from another origin, for example, the skin of the researchers holding the bones.

To sum up, both the author and the lecturer hold conflicting views on the existence of T. rex's tissues in its fossils.