Salazar-Estupiñán, Sianella Anais. “Students’ Perceptions of Difficulties in Learning Mendel’s Laws in Biology in the Second Year of Unified General Baccalaureate”. EKSIGMA, vol. 2, no. 3, Sept. 2026, pp. 21-31, https://eksigma.com/index.php/principal/article/view/32.