Two researchers are investigating the cause of colony collapse disorder (CCD) in honeybees. Researcher A hypothesizes that a systemic pesticide, neonicotinoids, is the primary culprit, weakening bees' immune systems and navigation. Researcher B argues that a combination of factors, including habitat loss, pathogens (like Varroa mites), and changing climate patterns, are collectively responsible, with no single primary cause.
Which of the following studies would most directly challenge Researcher A's hypothesis?
Correct: A
Researcher A hypothesizes that neonicotinoids are the *primary* culprit. If a long-term study shows that bee colonies in *pesticide-free* areas also experience significant declines due to other factors like mite infestations (Choice A), it directly challenges the idea that neonicotinoids are the *primary* cause. It suggests that other factors can independently lead to declines, supporting Researcher B's multi-factorial view and undermining the primacy of pesticides in Researcher A's argument. Choices B, C, and D would all, in various ways, support Researcher A's hypothesis or its implications.