A recent study examined the daytime

Answer choices

1. A

   No Impact / No Distinction3% picked this

   For both lemur populations, the primary competitors for food resources are species

   This helps explain why both lemur populations have an incentive to hunt for food nocturnally (fewer competitors), but this does nothing to explain why one group's nocturnal activity was significantly more than another's. It doesn't point to a factor that would be different between the two groups of lemurs.

   3%
2. B

   Correct70% picked this

   The primary predators for both lemur populations are high-flying birds that rely on their eyesight to

   Why this is right

   This points to a similarity, when we're looking for a difference, but wait — when it comes to a tree-dwelling lemur population that lives in trees with a full canopy leaves vs. a population that lives in trees where the leaves have fallen off (in winter), will they have different experiences of a "high-flying birds, their primary predator, which relies on eyesight to hunt prey during the day"? Sure! Since the bird is looking below, at the tops of trees, the lemurs who live underneath a canopy of leaves are much better hidden than are lemurs who live in a tree with no leaves. If you're a lemur who lives in a tree with no leaves in it, and you're primarily hunted by birds that use their eyesight to find you during daylight, then you're not going to want to be making yourself seen during the day. You'll keep your activity real low; try to stay hidden and motionless, so that the predator birds don't see you. You'll have to do your hunting for food at night, when the darkness will prevent the high-flying birds from being able to see you as well. Meanwhile, if you're a lemur living in a rain forest with a constant canopy of leaves, then it doesn't really matter whether you're out in the day or at night. The high-flying birds can't see past the canopy of leaves to see you moving about.

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

   70%
3. C

   No Impact / No Distinction5% picked this

   In both habitats, species of predatory snakes active during daylight are most active

   This answer might help explain why both populations have more nocturnal activity in the winter. Both of them are thinking, "Shoot — I wanna go out during the day, but I know in the winter there's an uptick of predatory snakes moving around during daylight. I'll just wait until it gets dark." This doesn't do anything to explain the difference though, because we don't have any common sense reason to think that rainforest lemurs would have a different experience of these snakes than deciduous lemurs would, so we don't have way to explain why deciduous lemurs are so much more active at night than rainforest lemurs are.

   5%
4. D

   No Impact - Population Size4% picked this

   The lemur population in the rain forest is twice the size of the population in

   The raw numbers of population size doesn't explain why the smaller population engages in way more nocturnal activity than the bigger population does. There's no common sense link between being a smaller population and thus having a bigger uptick in nocturnal activity during the winter.

   4%
5. E

   Unclear Impact17% picked this

   The lemur population in the rain forest eats both plants and insects whereas the population in the deciduous

   This does provide a difference between the two populations, but there isn't a common sense link between this difference and the one we know. Rainforest lemurs (year-round canopy of leaves, eat plants and insects, small uptick in nocturnal behavior during winter) vs. Deciduous lemurs (lose leaves during winter, eat only plants, big uptick in nocturnal behavior during winter) There's no obvious sense of why "if you eat only plants (rather than plants and insects), then you'll have a bigger uptick in nocturnal behavior during the winter".

   17%