Abstract
<p>Explanation and mechanistic reasoning are central to secondary biology education, yet a gap remains between theoretical models of learning and sustainable classroom practice. This article presents a framework that bridges this gap by providing teachers and students with a shared language for generating and evaluating biological discourse. Grounded in observable classroom interactions, the framework integrates two dimensions: (1) knowing versus understanding, distinguished by performance on foreseen versus unforeseen tasks, and (2) forms of biological discourse, distinguishing stating, describing, and explaining by increasing causal complexity. Together, these dimensions form a 2 × 3 matrix for practical classroom use. The article demonstrates how teachers can apply this matrix to structure questioning, assessment, and feedback, fostering a classroom culture of adaptive understanding and mechanistic explanation.</p>