Self-study
Antarctic seals dive to great depths and stay submerged for hours. ████ ██ ███ ████ ██████ ██ ██████ ████ ██ █████ ██████ ███ ████ █████ █████ ██████ ██ █████ ██████ ███████ ████ ███████████ ███████████ ████ ███ ████ █████ █████ █████ ████ █████ ██████████ █████ ██ █████ ████████
Summarize Argument
Researchers hypothesize that Antarctic seals store oxygenated blood in their spleens. The reasoning for this hypothesis isn't given.
Notable Assumptions
The researchers assume that it is possible to store oxygenated blood in the spleen, and that the seals would need to do so for some reason, perhaps because they need greater capacity to store oxygen than just in their bloodstream.
20.
Each of the following, if █████ ████████ ████ ███████ ███ ███ ████████████ ██████████ ███████
a
Horses are known ██ █████ ██████████ █████ ██ █████ ███████ ███ ███ ██████ █████████
This weakly strengthens the hypothesis by establishing that it is at least possible to store oxygenated blood in the spleen, as shown by horses, another mammal species.
b
Many species of ████ ███ █████ ██████ ████████ ██ █████ ██████ ███████
If anything, this would slightly weaken the argument by telling us that many seals already have a built-in \"overflow\" space for extra oxygen. This makes it less likely that Antarctic seals would need to store additional oxygenated blood in their spleens, since they might also be able to store oxygen in their muscles.
c
The oxygen contained ██ ███ ██████ █████ ███ ███████████ █████ █████ ██ ██████████ ██ ███████ ███ █████ ██████ █████ ██████
This strengthens the argument by telling us that seals do have a need to store oxygen somewhere besides their lungs and bloodstream. The spleen is one potential place for oxygen to be stored.
d
The spleen is ████ ██████ ██ ███ █████████ ████ ████ ██ ███████ ███████ ████ ██ ███ ████ ████ ██████
This strengthens the argument, because it suggests that Antarctic seals spleens’ have some special function related to long dives, which could well be the storage of oxygenated blood.
e
The spleens of █████████ █████ ███████ ███████ ██████████████ ██ █████ ███████ ████ ███ █████████ ██ ████ ██ █████ █████ ███████
This strengthens the argument, because it implies that Antarctic seals’ spleens are designed for storing blood.