Abstract :
This study aims to determine the profile of students' critical thinking skills in solving problems in the daily test questions of excretion system material at the high school level. This research is a descriptive study. The instrument used was a matter of critical thinking on the excretory system material that was based on questions in Sloane's book (2003), GRE Biology, and the National Examination (UN ) and interviews. The samples of this study were students of class XI IPA 1, XI IPA 2, and XI IPA 3 of SMAN 2 Pekanbaru, who had a high academic level and moderate academic level of 108 students. The results showed that the critical thinking skills of XI IPA 1, XI IPA 2 and XI IPA 3 of SMAN 2 Pekanbaru were in the very high category with a percentage of 80%. From critical thinking indicators based on focus indicators with 97% percentage in very high category, argument indicator with 65% percentage, conclusion indicator with 79% percentage in high category, situation indicator with 77% percentage in very high category, clarity indicator with 78% percentage in high category, indicator of further review with a percentage of 82% very high category. From the results of this study it can be concluded that the students of SMAN 2 Pekanbaru in the academic year 2019/2020 have critical thinking skills in the high category.