video explanation

text explanation

notice the structure of the sentence, “based their conclusions on faulty reasoning, claiming that scaly skin was common to all ectotherms.

the bolded part is the specific claim. look at part in parentheses and how it relates to the bolded part above:

(birds, which are ectothermic, do not have scaly skin).

this is a clear denial of the boldfaced part. the exact same thing happens with the second claim of scientists:

“…the dinosaur’s size could account for ectothermy.”

here is the objection (in parentheses) that states the boldfaced part is untrue:

(some adult dinosaurs weighed as little as ten pounds).

this points to answer (c): "provides a rebuttal to a commonly held view regarding the physical aspects of dinosaurs" — the commonly held view is that dinosaurs are ectotherms simply because they have scaly skin.


(a) is wrong because the author, while repudiating the claims that are in boldfaced above, uses the parentheses to say why the boldfaced parts are incorrect. he is not summarizing the claims in the parentheses.

(b) is talked about elsewhere in the passage. the focus of the parenthesis is on pointing out the inaccuracy to commonly made claims about the relationship between ectothermy and dinosaurs.

(c) the answer

(d) the theory the author supports (that of mesothermy) is described later in the passage.

(e) the information in parentheses might contradict the information that comes immediately before it; however, (e) mentions “dinosaur behavior”, which is not discussed in this passage.