Hanifa Nadhira Saputri. 037117136. Effect of Problem Based Learning Model Application on Learning Outcomes of Environmental Preservation Efforts. The approach taken is a quasi-experimental design of two groups at the Babakan Dramaga 04 State Elementary School, Bogor Regency. The subjects of this study were students of class V A and V B at the Bababkan State Elementary School Dramaga 04, Bo…