Djarawula, E.F., Prasetiyo, N.A. and Mitasari, Z. 2022. The Effect of Combination of Cooperative Learning Type STAD With NHT on Problem Solving Ability in Class X Students at High School. Journal of Biology Learning. 4, 2 (Aug. 2022), 84–93. DOI:https://doi.org/10.32585/jbl.v4i2.2375.