The development of technology and science has progressed very rapidly. Students are required to master various kinds of abilities, one of which is problem-solving ability. Problem-solving ability need to be developed in the learning process. The learning model that can facilitate students in practicing problem-solving ability is the Reading, Identifying, Constructing, Solving, Reviewing and Extending (RICOSRE) learning model. The purpose of this study was to determine the effect of using the RICOSRE learning model to the problem-solving abilities of Senior high school students on environmental change topic. This research was conducted at Senior High School 3 of Tangerang in January-June 2022. This type of research is quantitative with a quasi-experimental research method. The research sample amounted to 62 students with each class totaling 31 students who were selected by random sampling. Based on the t-test calculation at α = 0.05, a significance of 0.028 was obtained, which means that there is an effect of the RICOSRE learning model on the problem-solving abilities of students on environmental change topic.

The Bodogol Education and Nature Conservation Center (PPKA) area is a representative area for lowland mountain tropical forest ecosystems on the island of Java so that the biodiversity in this area is quite high. The purpose of this study was to determine the diversity of lichens found in the Rasamala and Cikaweni lines of PPKA Bodogol, Sukabumi, West Java. Biodiversity research is important because of the presence of lichens as part of biodiversity that is beneficial to the ecosystem.  The research method used is descriptive with exploratory techniques. Determination of trees that contain lichens is done by using purposive sampling technique. The results showed that in both pathways, lichens with crustose talus type dominated. On the Rasamala Line, 7 types of lichens were found, while on the Cikaweni Line, 5 types of lichens were found. The species diversity (H') of lichens in the Rasamala pathway was 1.51 while in the Cikaweni route it was 1.18. So based on the Shannon-Wienner formula, the biodiversity in the Rasamala and Cikaweni trails is in the medium category.