This paper analyses the opportunities for presenting knowledge that are created when assessment allows senior high school biology students to draw on linguistic and visual resources when constructing meaning in response to short-answer examination-style questions requiring a sequential explanation. Students within one senior high school biology class were given the opportunity to respond to an examination-style question through both written and visual representations. Analysis of the student responses for high and middle-achieving students, from a systemic functional linguistics perspective, indicates that high-achieving students use a broader range of grammatical forms more often than middle-achieving students to present key understandings of classification and composition within both written and visual representations. Including opportunities within assessment for students to express knowledge through written and visual representations allows for students to elaborate within their short-answer responses and to construct the broader range of representations that is valued within the discipline, but explicit guidance is required to support all students to make use of the complex grammatical patterns within written and visual representation. For senior high school biology students to be successful in the final stages of schooling, explicitness about the complex grammars of visual and written representations is required within curriculum and pedagogy.