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1. Figure 1 shows a stream flowing near a fertiliser factory - Edexcel - GCSE Biology - Question 1 - 2023 - Paper 2
Question 1
1. Figure 1 shows a stream flowing near a fertiliser factory. The factory burns coal as a source of energy. The factory releases waste into the stream and sulfur d... show full transcript
Worked Solution & Example Answer:1. Figure 1 shows a stream flowing near a fertiliser factory - Edexcel - GCSE Biology - Question 1 - 2023 - Paper 2
Step 1
1(a)(i) Calculate the factor by which the oxygen concentration changes from point A to point B.
Answer
To find the factor by which the oxygen concentration changes, we can use the formula:
ext{Factor} = rac{ ext{Oxygen concentration at B}}{ ext{Oxygen concentration at A}} = rac{4.5}{1.5} = 3Thus, the oxygen concentration increases by a factor of 3.
Step 2
1(a)(ii) Describe how the oxygen concentration changes from point A to point E.
Answer
The oxygen concentration shows an overall increase from point A to point B, then it levels off as it approaches point D. This indicates that the initial pollution from the factory significantly affects the oxygen levels, but as the water moves downstream, the concentration stabilizes.
Step 3
1(a)(iii) Explain which organism is a good indicator of water quality, and why.
Answer
The correct answer is the C sludgeworm.
This organism is a reliable indicator because it thrives in environments that are less polluted. In contrast, organisms such as freshwater shrimp, indicated by option A, are not found in polluted waters, making them poor indicators of water quality.
Step 4
1(a)(iv) Explain why biodiversity is greater in the stream at point D compared to E.
Answer
The biodiversity is greater at point D because:
- It is further from the fertiliser factory, which means there is less pollution affecting the water quality.
- The concentration of oxygen is higher at this point, providing a more suitable habitat for various organisms, thereby allowing them to survive and thrive.