A worker repeatedly lifted identical parcels from the floor onto a shelf. The mass of each parcel and the height of the shelf stayed the same.
The table shows measurements taken during the task.
| Measurement | After 2 minutes | After 8 minutes |
|---|---|---|
| Parcels lifted per minute | 8 | 16 |
| Breathing rate in breaths per minute | 20 | 24 |
| Breath volume in dm³ | 1.5 | 1.5 |
| Heart rate in beats per minute | 120 | 132 |
The volume of air moved into the lungs each minute is calculated using:
volume of air per minute = breathing rate × breath volume
Calculate the percentage increase in the volume of air moved into the worker's lungs each minute between 2 minutes and 8 minutes.
Near the end of the task, the worker's arm muscles began to contract less efficiently. Explain this observation. Use the results and your answer to part (a).
92 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.