IB skill practice

Evaluate biological investigation design and data

Paper 1, Paper 2 5 marks Difficulty 4

Identify variables in investigation

A student in a immunity case study tests how the result affects photosynthesis rate while keeping temperature and carbon dioxide constant. Identify the independent variable. 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.