Muscles become fatigued after long periods of vigorous exercise. What causes muscle fatigue?
A build-up of lactic acid in the muscles, so they contract less strongly
A build-up of glycogen in the muscles, so they contract less strongly
A build-up of glucose in the muscles, so they contract more strongly
A build-up of oxygen in the muscles, so they contract more strongly
51 exam-style questions on AQA GCSE Biology 4.2 Respiration, covering 4.2.1 Aerobic and anaerobic respiration, 4.2.2 Response to exercise, and 4.2.3 Metabolism. Each one has a worked solution and a mark scheme showing where the marks go.