Participating in research activities, students construct, expand and restructure their knowledge. Such a research approach to education, along with research activities, knowledge and skills, develops autonomy, communication skills and conceptual understanding of the characteristics of higher cognitive levels. The research was conducted in order to determine if the students of high school students who approach the biology competition with the research work achieve better success in the written exam of the knowledge or the students who approach it without research work, or establish the correlation of research work on success in solving the tasks of higher cognitive levels. The research used the written tests of knowledge from the county competition of Biology high schools conducted in 2015 as well as research paper work selected by members of the State Commission. A total of 376 students attended the county competition, of which 44 students participated in competitions in knowledge and competitions in research works. The research work has been analyzed because students can participate individually or in pairs at the research work. The research found that students who approach the competition only in the written examination of the knowledge achieve a better overall solution from the knowledge than the students who approach the competition together with the research work. It has also been found that activities invested in research work contribute to strengthening skills that are characteristic of higher cognitive levels such as analysis, synthesis, and development of critical thinking that enable students to solve problems, achieve understanding and discover new meaning. It was established that tasks related to the topic of research work affect the overall solving of written knowledge.