TPO 24

Both the reading and the lecture are about the rex's leg bone examination. Recently scientists have examined these bone and think that materials that seem to be remains of blood vessels are been seen in the rex's leg bone. The author of the reading states that there are three reasons why they think that the fossils were replaced by minerals. However, the lecturer opposes all the reasons, which are mentioned by the author.

First and foremost, the professor points out that soft bones are usually colonized by bacteria which might have left traces residues on these bones. This is opposed by the reading, which claims that the breaking of the fossilized leg bone revealed many small branching channels inside,which corresponded to hollows in the bones.

Secondly, the lecturer mention that the spheres are found in other animals like primate that do not have blood vessels. Therefore, these identical spheres do not provide an evidence of the presence of red blood cells. Nevertheless, the article assert that the presence of spheres that could remain in red blood cells contain iron, which is a vital material of the red blood cells.

Finally, the reading passage suggests that researchers found collagen in the leg bone. consequently, collagen is a ferrous protein that is a main component of living bone tissue. On the other hand the professor refutes this point by saying that the collagen cannot last longer than 100,000 years. These fossils bones were 70 million years old, which means that it is impossible for the collagen to survive and be present for that long. In addition, the professor elaborates on that telling us that the collagen could have been fallen from the researchers skins.