Antarctic seals dive to great depths and stay submerged for hours. They do not rely solely on oxygen held in their lungs, but also store extra oxygen in their blood. Indeed, some researchers hypothesize that for long dives these seals also store oxygenated blood in their spleens. Each of the following, if true, provides some support for the researchers' hypothesis EXCEPT: ['The spleens of Antarctic seals contain greater concentrations of blood vessels than are contained in most of their other organs.', "The oxygen contained in the seals' lungs and bloodstream alone would be inadequate to support the seals during their dives.", 'The spleen is much larger in the Antarctic seal than in aquatic mammals that do not make long dives.', 'Many species of seal can store oxygen directly in their muscle tissue.']