In recent years, there has been an effort to develop reform-oriented and inquiry-based early science instruction. Preliminary studies suggest that participation in inquiry-based learning activities promotes preschoolers' learning and interest in science. In addition, science education in early childhood is of great importance to many aspects of a child's development, and researchers suggest that science education should begin during the early years of schooling. The participants of this intervention were a total of 115 preschool students from six different public schools in a western, urban public-school district in California, USA. In this specific intervention analysis for one classroom only, a small sample of a total of 18 (4-5-year-old) Latino/multilingual preschool students (n =18; 9 boys and 9 girls) were exposed to an inquiry-based curriculum designed to teach them about health concepts in the context of science activities. The general goal of the study was to explore how different types of questions posed by an instructor related to children's biological conceptual understanding. The author hypothesized that children who responded to more teacher questions would exhibit higher levels of conceptual knowledge about health/biology concepts in a posttest interview. This intervention confirmed that students who engaged in question-asking and generated explanations during the lessons gained a deeper conceptual knowledge as evidenced by more sophisticated knowledge of cold/flu prevention concepts in the posttests. Thus, these preliminary findings demonstrated that this inquiry-based curriculum was effective at helping children understand the processes of contagion and illness. Finally, understanding how preschool students engage in science inquiry lessons could greatly benefit researchers, educators, and practitioners to maximize the students' conceptual knowledge about science.