IB skill practice

Analyse homeostatic control systems

Paper 1, Paper 2 5 marks Difficulty 4

Compare negative and positive feedback

A control-system comparison in a plant systems lab shows one pathway restoring a variable to a set point and another amplifying contractions during birth. Distinguish the feedback types. 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.