ChallengeMaker
B is bad for one simple reason: the role of the first bold-faced portion is indicated wrongly. "certain vital biological processes...are slower in these areas than is usual for the inspected species" is not something the author critiques
Why not.
The author does not say a thing about "the chemical being harmful or not" , all that he says is that he is not happy with the conclusion derived from a premise.In effect he is just critiquing the "logical deduction".
If in fact he made a stmt like "therefore the chem is not harmful" they we might conclude that he critiqued the biologist's claim.
NOTE : he says the conclusion is unwarranted ( NOT right or wrong).For all that we know the author might not be a biologist, but a plain logician hired to evaluate the logical validity of a claim !
BTW - what is the author's position here as stated in C ( I think he just points a flaw on the biologists claim without having a position)
ChallengeMaker what is your opinion on this ?
HMTG.
PS : had picked B.
B is wrong because first BF contains no argument with which the author would take issue. The author says nothing about whether he disagrees with the fact that "certain bio processes are slow" but he clearly disputes the professor's argument which is built on evidence in BF1
Note that C says that the author disputes the professor's argument (not the conclusion). This wording describes the situation pretty accurately because the author indeed disputes the arguemnt i.e. how it is constructed. He does not like the logic behind the argument so we can say that he disputes the argument.
Finally, the author's main point in this passage is to prove that the professor's claim is unwarranted. This is the author's position; it can be put into such words: "it is premature to conclude that chlorocetin is a dangerous chemical affecting natural world". Pretty nice and clear position, don't you agree?