Self-study
Body temperature can be estimated by the relative proportion of two oxygen isotopes in bone. ████ █████████ ███████ ████ ████████ ███████ ███████ ████ █████████ ███ ██████ ███ ████ ████ ███████████ ██ █████ █████ ██ ██ ███ ████ ██ █████ ███████ ██████████ ███ ████ ████ ███████████ ██ ████████████ ███████ █████ ██ ████ ██████ ████ ███ ████ ███████████ ██ █████ ██████ █████ █████████ ████ ████████ █████████████
Summarize Argument
Dinosaurs were likely warm-blooded because the oxygen isotopes in their bones suggest that their limbs had the same body temperature as the rest of their body. And typically, the body temperature of modern cold-blooded animals much is higher than their limbs.
Notable Assumptions
The author assumes that the discrepancy in the body/limb temperature of modern cold-blooded animals was the same as cold-blooded animals during the time of the dinosaurs. The author also assumes that the process of determining body temperature from bones is applicable to dinosaur fossils.
2.
Which one of the following, ██ █████ ████ █████████ ███████ ███ █████████
a
Large warm-blooded animals ████ █████ ████ ████ ███████████ ████████ ██████ ████ ███ ████ ███████████ ██ █████ ██████
This does not weaken because dinosaurs' core body and limb temperature are still much closer to the ratio of warm-blooded animals. Thus, this does not weaken the claim that dinosaurs were warm-blooded.
b
The fossilization process ██████████ ███████ ██ █████ ████ ████ █████ ████████ ██████ ███████ ██████ ██████ ██ ██████████
This weakens the argument because it casts doubt on the process by which the evidence was discovered. If the fossilization process changes the oxygen distribution, then the evidence about the body temperature cannot be relied on to reach a sound conclusion.
Alternate explanation
Alternate explanation
Weaken: Introduce or support an alternate explanation for a phenomenon.
Strengthen: Helps to eliminate an alternate explanation for a phenomenon.
c
Oxygen was more ████████ ██ ███████ ██████████ ██████ ███ ██████ ██ █████ ███ █████████ ██████
You must make several unwarranted assumptions to make this work. The fact that more oxygen was prevalent in the atmosphere does not mean dinosaur bones have more oxygen. AC B does a much better job of weakening the process of how the evidence was collected.
d
Small warm-blooded animals ████ ████ ████ ██ ████ ████ ███████ ████ ████████████ ████ ██ █████ ████████████ ███████ ████ ██████████
This does not weaken the argument that dinosaurs are warm-blooded. This AC just compares small and large warm-blooded animals. You have to make many unwarranted assumptions for this to work.
e
Warm-blooded animals are ████ ██████ ███ ███ ████ ██████ ████ ████████████ ████████
This is irrelevant to the argument’s reasoning. This just provides a characteristic of warm-blooded animals but does not challenge the evidence or reasoning in the stimulus.