Identify the most recent common ancestor
A phylogenetic tree in a chromosome modelling activity places species 1 and species 2 on sister branches joined by the nearest internal node. State what that node represents. Use the diagram labels, data values, or inheritance pattern before writing the answer. Enter the answer and choose the interpretation that best matches the HL Biology evidence.
Worked practice: biological evidence and answer
Use the labelled biological evidence first, then connect it to the final answer.
Write a full answer
Now write the response in full, in your own words — this is what the exam asks for. The AI marks it on the same moves you built above (focus, evidence, technique, judgement) and gives feedback on reasoning, evidence, and expression.