Explain ventilation gradient
A ventilation model in a immunity case study shows fresh air entering the lungs and carbon dioxide-rich air leaving. Explain why ventilation helps diffusion. Use the diagram labels, physiology pathway, feedback loop, or data values before answering. Enter the answer and choose the interpretation that best matches the biological 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.