Boris Yarmakhov, Sergey Sumatokhin. A DIGITAL ADAPTIVE TEXTBOOK FOR SECONDARY BIOLOGY EDUCATION: DEVELOPMENT AND TESTING: Received: 12th March 2026, Revised: 22th April 2026, Accepted: 05th May 2026, Date of Publication: 12th June 2026. pijtel [Internet]. 2026 Jun. 12 [cited 2026 Jun. 15];10(1):20-9. Available from: http://www.grdspublishing.org/index.php/PUPIL/article/view/3219