AbstractThe purpose of this qualitative case study was to understand and describe the existing teaching and learning activities of Content and Language Integrated Learning (CLIL) conducted in the selected Biology classrooms in Peninsular Malaysia. The study was guided by three research questions, focusing in the nature of the teaching and learning activities, the cognitive levels reflected by the activities through the lens of Revised Bloom’s Taxonomy (RBT), and the language skills that could be learned through the activities in Biology learning. Three experienced Biology Excellent Teachers and their students were purposively selected as respondents in this study. The data collected through classroom observations, semi-structured interviews, and document reviews were validated through member checking and triangulation. Firstly, the findings suggested that the five main nature of the CLIL activities are interactive, studentcentered, teacher-centered, ICT integrated and exam-oriented. Secondly.....