EFFECTS OF KELLER SYSTEM OF INSTRUCTION (KSI) ON STUDENTS’ ACADEMIC ACHIEVEMENT IN BIOLOGY Dr. Christiana Ogonna Odimkpa1, Dr. Adaora Phina Anudu1, Prof. S. O. Abonyi1 & Dr. Chibueze Utum Mgboro2 The study investigated the Effect of Keller System of Instruction (KSI) on students’Achievement in Biology. The design of the study was a quasi-experimental, nonequivalent pretest …