Research suggests that REM sleep in animals is homeostatically regulated: animals compensate for periods of REM sleep deprivation by increasing subsequent REM sleep. When on land, fur seals get enough REM sleep, but during the weeks they’re in the water, they get almost none. In a study of fur seals’ sleep habits, researchers recorded the REM sleep (as a percentage of baseline) of fur seals once they had returned to land. They concluded that REM sleep may not be homeostatically regulated in fur seals, citing as evidence the fact that the seals in the study ______blank
","stem_html":"Which choice most effectively uses data from the graph to complete the text?
","rationale_html":"Choice C is the best answer. If REM sleep were homeostatically regulated in fur seals, then all the seals would compensate with REM levels significantly over baseline after going weeks without REM. We’d also expect the seals to maintain those elevated REM levels for some time. Since seals B and C return very quickly to baseline REM levels, this suggests that REM sleep in fur seals may not be regulated homeostatically.
Choice A is incorrect. This doesn’t support the conclusion. If REM sleep were homeostatically regulated in fur seals, then we’d suspect the seals to sustain REM levels well above baseline for a prolonged period in order to compensate for weeks of REM deprivation while in the water. Whether or not there’s a reduction in REM sleep from day 1 to day 2 doesn’t tell us how REM sleep on those days relates to baseline, which is where our focus should be. Choice B is incorrect. The y-axis of this graph doesn’t depict baseline levels of REM sleep, but rather shows REM sleep as a percent of baseline. Choice D is incorrect. The graph doesn’t depict REM sleep while in the water for the seals in the study. Additionally, we’re told fur seals get no REM sleep while in the water, which is significantly different to the values shown in the graph for after they return to land.
","correct_answer":["C"],"has_media":true,"has_mathml":false,"has_table":false,"source_created_at":"2023-08-02T20:25:59.369000+00:00","source_updated_at":"2023-08-02T20:25:59.369000+00:00","options":[{"label":"A","content_html":"didn’t show significantly less REM sleep during the second day after returning to land than they did during the first day.
","ord":0},{"label":"B","content_html":"showed no significant differences from one another in baseline levels of REM sleep.
","ord":1},{"label":"C","content_html":"didn’t consistently demonstrate a significant increase in REM sleep after their period of deprivation in the water.
","ord":2},{"label":"D","content_html":"showed no significant difference between REM sleep after returning to land and REM sleep while in the water.
","ord":3}],"attribution":{"source_id":"cb_question_bank","source_name":"College Board digital SAT question bank (community dump)","rights_holder":"College Board","canonical_url":"https://satsuitequestionbank.collegeboard.org/","retrieved_from":"https://raw.githubusercontent.com/mdn522/sat-question-bank/main/data/cb-digital-questions.json","attribution":"SAT practice questions © College Board, from the official SAT Suite Question Bank. Retrieved via the community dump at github.com/mdn522/sat-question-bank.","disclaimer":"SAT® and PSAT/NMSQT® are trademarks registered by the College Board, which is not affiliated with, does not sponsor, and does not endorse this project.","license":"College Board copyright; source repository carries no licence. Local use only.","redistributable":false,"item_count":2017}}