“THE RELATIONSHIP BETWEEN 21ST CENTURY SKILLS AND STUDENT LEARNING OUTCOMES THROUGH THE APPLICATION OF PROBLEM BASED LEARNING MODELS IN CLASS X ENVIRONMENTAL CHANGE MATERIALS AT SMA NEGERI 5 MEDAN T.P 2023/2024”, JPP, vol. 13, no. 1, pp. 20–28, Mar. 2025, Accessed: Mar. 20, 2026. [Online]. Available: https://jurnal.unimed.ac.id/2012/index.php/pelita/article/view/67193