The third in a series of evaluative reports on "Me and My Environment", a group-centered biological sciences program for educable mentally handicapped (EMH) adolescents, provides information about the curriculum design, the analysis and revision of curriculum materials, the gathering and processing of field test data, and a comparison of two representative seventh grade classrooms which were part of the field test. In a section on curriculum design, the rationale for selecting and organizing curriculum content is discussed; the program is traced from design to material development; and curriculum design theories and underlying assumptions are explained. Analysis and revision of curriculum materials is considered in relation to activities such as content reviews by experts and by staff members and a matrix analysis to determine emphasis on curricular components such as environmental themes and problem-solving skills. Described are problems, concerns, and costs of collecting and processing data (from field-test classes, teachers, students, and observers) to be used in evaluating curriculum effectiveness. Contrasted in a case study of the two classes are variables influencing effective use of the science curriculum such as classroom climate, student/teacher interaction, and teaching approaches that stress learning versus approaches that emphasize student behavior. Included are many photographs, charts, and graphs. (LH)