This is the student's text of one unit of the Intermediate Science Curriculum Study (ISCS) for level III students (grade 9). This unit focuses on diversity in human populations, measurement, and data collection. Numerous activities are given and optional excursions encourage students to pursue a topic in greater depth. Data tables within the workbook format indicate where responses are expected. Illustrations accompany all instructions and the students are expected to select the proper equipment for experiments based on the illustrations. (SA)