<![CDATA[This study aims to identify students' conceptual understanding and analyze indications of misconceptions in monohybrid cross material using the Certainty of Response Index (CRI) method. The study was conducted at SMP Negeri 2 Singorojo with 30 ninth-grade students as research subjects. Data were collected using a diagnostic test accompanied by a Certainty of Response Index (CRI) scale to identify students' confidence in their answers. The data were analyzed by classifying students' responses into four categories: Conceptual Understanding (PK), Conceptual Understanding with Less Confidence (PKKY), Misconceptions (M), and Conceptual Uncertainty/Do Not Know the Concept (TTK). The results showed that 40% of the analyzed responses were classified as Conceptual Understanding, 17% as Conceptual Understanding with Less Confidence, 37% as Misconceptions, and 6% as Conceptual Uncertainty/Do Not Know the Concept. The highest proportions of suspected misconceptions were identified in the sub-concepts of basic genetics, particularly genotype and phenotype, gamete formation and segregation, and determining cross results using Punnett squares. These findings indicate that students experienced substantial conceptual difficulties in connecting genetic representations, allele segregation, and the probability of offspring inheritance. This provides an empirical basis for designing subsequent instructional interventions that emphasize conceptual visualization, genetic processes, and contextual learning to strengthen students' understanding of monohybrid crosses.]]>
