Support Tent caterpillars' routes between their nests and potential food sources are marked with chemical traces called pheromones that the caterpillars leave behind. █████████ ██████ ████ ████ ███████ ████ ██ ███ ████ ███ ██████ ████ ███████ ████ ███ ██████ ███████████ ██████ ████ ████ ██████ ██ ████ ██ █ ████ ███████ █████ ████ ████████████ ███ ██████████ █████ ███ ██████ ███████ ████ ██████ ██ ████████ █████████ █████ ████████ ██ ███ █████████ ██ ███████████ ██████████ ███ ████████ ██ ████ ██ █████ ███████ ██ ███ ███████ █████ ██ █████
The author hypothesizes that tent caterpillars engage in communal foraging. This is because tent caterpillars mark their routes to food with pheromones, and moreover mark routes to food more heavily than routes that don’t lead to food.
The author assumes that tent caterpillars are attempting to convey information to one another by marking their trails, and that other caterpillars can pick up on such markings. If tent caterpillars don’t sense pheromones, then these trails would be useless.
Which one of the following, ██ █████ ████ ███ ████ ███████ ██ ███ █████████
A hungry tent ███████████ ██ ████ ██████ ██ ██████ ███████ ██████ ██████ ████ ███████ ██████ ███████
In other words, tent caterpillars can indeed pick up on pheromones, and they understand what heavily marked trails signify. This confirms two of the author’s assumptions, strengthening the argument.
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
Tent caterpillars can ██████ ███ ████████ ███ ███ ███ █████████████ ██ ███████████
If tent caterpillars can’t detect the concentration of pheromones, then the author’s claim about heavily marked paths becomes unimportant. This weakens the argument.
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).
Sometimes individual tent ████████████ ████ ███ ██████ ██ ███ ████ █████ █ ████ ██████ ██ ████████
This is irrelevant, because it doesn't confirm or deny the social role of the caterpillars' pheromone trails.
The pheromones left ██ ████ ████████████ ███ █████████ ████ ███ ██████████ ████ ██ █████ ████████
We still don’t know if tent caterpillars can sense pheromones, or whether pheromones are used for communication. Whether the pheromones are specific or not doesn't help us.
The pheromones that ████ ████████████ █████ ██████ ███ ██████████ ██ ███████ █████ ███████ ██ █████████████
We need to know if tent caterpillars can detect pheromones themselves. It doesn't matter what other caterpillars can do unless that tells us more about tent caterpillars, which this doesn't.