OCR GCSE Biology A · J247
Specification PAG 6 · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: Physiology, responses, respirationIf both are needed at nearly the same moment, two observers can count them simultaneously: taking one count and then the other would allow extra recovery time before the second measurement. Record the time at which each reading is taken.