Cod can only breed when they are at least 50 cm long.
Scientists measured the lengths of all the cod caught by one fishing boat using nets with a mesh size of 80 mm.
The Table shows some percentiles of the lengths of the cod caught.
Table
| Percentile | Length of cod in cm\text{cm}cm |
|---|---|
| 10th | 28 |
| 25th | 35 |
| 50th | 42 |
| 75th | 49 |
| 90th | 58 |
State what the 75th percentile value of 49 cm shows about the cod caught.
Use the Table to estimate the percentage of the cod caught that were too short to breed.
Explain your answer.
Explain why using nets with a larger mesh size helps to conserve cod.
Many countries have agreed to use nets with a larger mesh size.
Explain why this agreement is difficult to monitor.
109 exam-style questions on OCR GCSE Biology 6.1 Monitoring and maintaining the environment, covering 6.1.1 Field investigation of distribution and abundance, 6.1.2 Human interactions and biodiversity, 6.1.3 Maintaining biodiversity, and 6.1.4 Environmental change and distribution of organisms. Each one has a worked solution and a mark scheme showing where the marks go.