A recent presentation to the American Geological Society presented evidence to support the idea that the arms were well-adapted for slashing attacks on T. rex's prey.

The reading passage claims that the T. rex arms were well adopted for slashing attacks on T. rex's prey and provides some evidence to prove this claim. On the other hand, the professor finds all the ideas dubious and brings up some evidence to refute them all. First, the author argues the fact that the strong muscles which were attached to the T. rex arms provided enough power to attack by these arms to the prey. On the contrary, the lecturer believes the idea that these arms were not necessary for T. rex because a bunch of fossils has been discovered until now that show T. rex arms were broken and if these arms were necessary for T. rex; therefore, they should die. For the second reason, the reading passage mentions that because of two claws, T. rex could concentration its force on to the arms and killed its prey, but the speaker believes that T. rex had strong enough teeth which height about 30 centimeters and did not need to kill its prey with its arms. Finally, the reading mentions that the size of the T. rex arms was well-suit for catching its prey to eat them and also states the fact that the bigger size is, the better, but it has a considerable energy cost for T. rex. Conversely, the professor states that the size of the T. rex arm is proper for youngs ones and not for adults, so the arms do not grow as T. rex growth because it became useless for adult T. rex.