“…The teacher can facilitate learning and provide motivation to learn the ecosystem using problem-based learning model (Ismail, Harun, Zakaria, & Salleh, 2018;Kong, Qin, Zhou, Mou, & Gao, 2014;Simamora, Simamora, & Sinaga, 2017;Sulaiman & Eldy, 2014). Problem-based learning in the classroom provides reading, writing, speaking, and discussing critically to improve the critical thinking skills of students (Chaijaroen, Kanjug, & Samat, 2012;Chen & Osman, 2017;Fahim & Pezeshki, 2012). It can train critical thinking skills of students more optimal and facilitates them to make reasoning as well as solving the problem which provides student-centered learning activities (Ahrari et al, 2016;Habimana & Stambach, 2015).…”