Self-study
Among small- to medium-sized marine mammals such as seals and dolphins, the longer an animal can stay submerged during a dive, the greater the depth the animal can reach. ████████ ███ ████ ██ ███████ ██████ ████ ████████ ███ █████ ████ ███ ████████ █████ ███ ████ █████████ ██████ ████ ███████ █████ ████
Stimulus Summary
Fact 1: Among small-to-medium-sized marine mammals, the longer an animal can stay submerged during a dive, the greater the depth it can reach. This means submersion time and diving depth go hand-in-hand. If we know which of two animals dives deeper, we also know which one stays submerged longer, and vice versa.
Fact 2: Dolphins can dive deeper than northern fur seals. Since depth and submersion time go together, we can also infer that dolphins stay submerged longer than northern fur seals.
Fact 3: Elephant seals can stay submerged longer than Weddell seals. By the same reasoning, we can infer that elephant seals can dive deeper than Weddell seals.
Here's what we know:
🌊 surface
🦭 N. fur seals
🐬 Dolphins
?
🦭 Weddell seals
🐘 Elephant seals
↓ deeper / longer submerged
Keep in mind that we don't know how the pair on the left compares to the pair on the right.
Anticipation
This is a "could be true EXCEPT" question, which means four of the five answers could be true and one must be false. We're looking for the one that must be false.
Since we know the ranking within each pair but not across pairs, most answers that only make cross-pair comparisons can easily be true. The answer that must be false will force a contradiction with the orderings we've already established.
Analysis by Kevin_Lin
25.
If the information above is █████████ ████ ████ ██ ███ █████████ ██████████ █████ ██ ████ ███████
a
Dolphins can dive ██ ███████ ██████ ████ ███████ █████ ████ ███ ███ ██ ██████ ██ █████ ██ ████████ █████ ████
b
Weddell seals can ████ █████████ ██████ ████ ████████ ███ █████ ████ ███ ████████ ███ ████ ██ ███████ ██████ ████ ███████ █████ ████
c
Weddell seals can ████ ██ ███████ ██████ ████ ████████ ███ ███ ███ ████ █████████ ██████ ████ ████████ ███ █████ ████
d
Northern fur seals ███ ████ █████████ ██████ ████ ████████ █████ ████ ███ ███████ █████ ███ ████ ██ ███████ ██████ ████ ████████ ████
e
Northern fur seals ███ ████ █████████ ██████ ████ ███████ █████ ████ ███ ████████ █████ ███ ████ ██ ███████ ██████ ████ ████████ ███ █████ ████