OCR GCSE Biology B · J257
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: Controlling FactorsA control group or control condition is a baseline for comparison. For example, plants receiving no fertiliser could form the control group when testing fertiliser, while water volume, light and plant species are control variables in both groups. An investigation may require several control variables even when it has no separate control group.