IB skill practice

Evaluate biological investigation design and data

Paper 1, Paper 2 5 marks Difficulty 3

Evaluate control variable

In an enzyme investigation from a neurobiology tutorial, pH is not controlled while temperature is being tested. Explain why this weakens validity. 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.