The study sought to find out the biological topics in the National Curriculum that students in Senior Secondary School Two (SSII) have difficulties in learning, the reasons why students have difficulties in learning such topics in biology, and to suggest ways of improving the effectiveness of the teachinglearning process of biological topics. For these purposes, a questionnaire consisting of both closed and open-ended items was administered to the students in the data collection procedure. The instrument was administered to 400 SS II students in some selected secondary schools in Education District V of Lagos State. The data collected were analyzed both qualitatively and quantitatively. The result showed that there was no significant difference in the perception of students on difficult topics in Biology on the basis of their subject areas-Science, Commercial or Arts (F (2, 397) = 1.523, P > 0.05, Partial η 2 = .008, R 2 =.003). Moreover, findings revealed that students usually have difficulties in five major topics. Among of which were nutrient cycling in nature, ecological management, conservation of natural resources, pests and diseases of crops as well as reproductive system in plants. However, teaching strategies, students' attitude, inadequate learning resources and students' learning habits were the reasons adduced by students of the perceived difficult topics. In remedying the problem, the students suggested the use of varied strategies that would involve appropriate instructional materials, use of hands-on and minds-on strategy, integrating biological concepts to daily life and provision of adequate and functional resources.

Instruction involves the art of impacting knowledge unto students in order to bring about a change in behaviour as a result of experiences from the impacted knowledge. The art of impacting knowledge requires the teacher selecting appropriate pedagogical strategies that would bring about appreciable academic achievement among the students. This study was carried out to examine the effects of peer-assisted learning strategies as pedagogical approaches on students' academic performance in basic science. The study involved 213 students randomly sampled from eight junior secondary schools in education district iii of lagos state. Basic science achievement test on (bsat) was used for data collection. Data collected were analyzed with the use of mean scores and analysis of covariance (ancova). Findings revealed that students exposed to peer-assisted learning strategies generally outperformed those in the traditional lecture group with average mean sores of 10.92 and 7.44, respectively. Furthermore, results showed that there was a significant effect of treatment on students' achievement scores in basic science, f (3, 204) = 24.23, p<0.05, partial ɳ 2 = .263, r 2 =.272.