By Devin Marsh, editorPublished 1 March 2026Last checked 31 July 2026
This item was written for this site and solved a second time from scratch before it went up, so that exactly one answer survives. The byline is a masthead name, explained in full on who writes this, and the sourcing rules are set out on the standards page.
Passage: "Karl von Frisch's decoding of the honeybee waggle dance showed that the angle of the dance relative to vertical encodes the direction of a food source relative to the sun, while the dance's duration encodes distance. Later research complicated this picture in productive ways: richer food sources provoke longer and more vigorous dances, so the dance conveys quality as well as location, and foragers weigh dance information against their own prior knowledge of a site, sometimes ignoring dances that point to familiar, depleted patches." The passage is primarily concerned with...
Ademonstrating that von Frisch's interpretation of the waggle dance was fundamentally mistaken
Bdescribing what the waggle dance communicates and how later findings refined that account
Ccomparing the navigation abilities of honeybees with those of migratory birds
Dexplaining the physiological mechanism by which bees produce the waggle dance
Ewarning that declining bee populations threaten scientific study of the dance
Try it before you scroll. Two minutes on the clock, then commit to an answer.
Correct answer: B
Map the passage’s structure before reading choices. Sentence one: von Frisch’s decoding (direction and distance). Sentence two: later additions (quality, and foragers weighing dances against prior knowledge). Nothing is overturned; the later work is described as complicating the picture “in productive ways,” which means refinement, not rejection.
(B) captures both halves: what the dance communicates (location, distance, quality) and how later findings refined the account (context-dependent use by foragers). Correct.
(A) overstates: refinement is not refutation. The passage credits von Frisch’s decoding as the foundation.
(C) introduces birds, which never appear.
(D) asks about the mechanism producing the dance (muscles, neural control), which the passage never discusses; it is about what the dance means.
(E) raises population decline, an idea with zero textual support.
Main-idea questions punish choices that are true-sounding but unsupported, and choices that match one sentence while missing the whole. (A) matches the later-research sentence but misreads its tone. (B) is the only option that covers both sentences with the right relationship between them.