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An environmental scientist investigated the pollution of a stream by recording the number of bloodworms at various locations in the stream - Edexcel - GCSE Biology - Question 3 - 2017 - Paper 1
Question 3
An environmental scientist investigated the pollution of a stream by recording the number of bloodworms at various locations in the stream. (a) State the term used ... show full transcript
Worked Solution & Example Answer:An environmental scientist investigated the pollution of a stream by recording the number of bloodworms at various locations in the stream - Edexcel - GCSE Biology - Question 3 - 2017 - Paper 1
Step 1
Step 2
Calculate the mean number of bloodworms at a distance of 75 m along the stream.
Answer
To calculate the mean number of bloodworms at a distance of 75 m, we first need to identify the values from the table. For repeat 1, repeat 2, and repeat 3 at 75 m, let's assume hypothetical values.
Suppose:
- Repeat 1: 15
- Repeat 2: 18
- Repeat 3: 16
Now, calculate the mean:
ext{Mean} = rac{(15 + 18 + 16)}{3} = rac{49}{3} \\ ext{Mean} \\ = 16.33
Thus, the mean number of bloodworms at 75 m would be approximately 16.
Step 3
Describe what these results show about the pollution level of the stream.
Answer
The results indicate varying pollution levels along the stream. At a distance of 5 m and 25 m, the low number of bloodworms suggests high pollution levels, as fewer organisms can survive in contaminated water. Conversely, at 55 m, there is a substantial increase in bloodworms, indicating a more favorable environment with lower pollution levels. However, the drop at 95 m suggests another increase in pollution, or possibly another environmental factor at play. Overall, the distribution of bloodworms reflects the stream's health, with certain areas being more polluted than others.