PT151 S2 Q18 ExplanationIn grasslands near the Namib Desert

Answer choices, explained

1. A

   Correct52% picked this

   Dying grass plants within newly forming fairy circles are damaged only

   Why this is right

   This is the kind of evidence the hypothesis needs. Termites burrow underground, where the roots are. If grass plants in newly forming fairy circles are damaged only at the roots — not at the leaves, stems, or above-ground parts — that points to an underground cause. Termite burrowing fits exactly. The damage pattern matches the proposed mechanism, which strengthens the case that termites are doing the damage rather than merely living in already-damaged areas.

   Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

   52%
2. B

   Opposite10% picked this

   The grasses that grow around fairy circles are able to survive even the harshest and most prolonged

   If grasses around the circles can survive even the harshest droughts, then drought-resistance is not what distinguishes circle interiors from circle perimeters. That suggests something other than termite activity might be at work — possibly something specific about the soil or chemistry inside the circle. If anything, this answer raises the question of why termites would kill grass that is otherwise drought-hardy. It does not strengthen the termite hypothesis; it reframes the puzzle in a way that points elsewhere.

   10%
3. C

   No Impact3% picked this

   The soil in fairy circles typically has higher water content than the soil in areas

   Higher water content inside fairy circles is interesting, but it does not specifically point to termites. Higher water could be a consequence of the circles forming for some other reason (no plants drinking the water), or it could even be evidence for a non-termite cause. This answer does not connect the formation of circles to termite burrowing.

   3%
4. D

   No Impact7% picked this

   Fairy circles tend to form in areas that already have numerous

   Clustering of fairy circles is consistent with a termite explanation (nearby colonies could spread) but also consistent with many non-termite explanations (soil chemistry, vegetation patterns, water flow). Without a specific link to termites, clustering does not single out termite burrowing as the cause. The hypothesis needs more than just spatial pattern.

   7%
5. E

   No Impact29% picked this

   Species of animals that feed on sand termites are often found living

   The argument already establishes that termites are present in every investigated circle. That predators of termites also live nearby just confirms — by a roundabout route — that termites are there. But the question is whether termite burrowing causes the circles, not whether termites are present. This answer does not bear on causation.

   29%