Statements: 1. All fish are grey in colour
2. Some fish are heavy
Conclusions: 1. All heavy fish are grey in colour
2. All light fish are not grey in colour

Options

A. only conclusion 1 follows,
B. only conclusion 2 follows,
C. either conclusion 1 or 2 follows,
D. neither conclusion 1 nor 2 follows,

Answer

To solve the problem, we will analyze the statements and conclusions step by step.

### Step 1: Analyze the Statements
1. **Statement 1**: "All fish are grey in colour."
- This means that every fish, without exception, falls into the category of grey fish.

2. **Statement 2**: "Some fish are heavy."
- This indicates that within the group of fish, there exists a subset that is classified as heavy.

### Step 2: Analyze the Conclusions
1. **Conclusion 1**: "All heavy fish are grey in colour."
- Since Statement 1 states that all fish are grey, and since some fish are heavy, it follows that all heavy fish must also be grey. Therefore, this conclusion is true.

2. **Conclusion 2**: "All light fish are not grey in colour."
- This conclusion suggests that light fish (which are not heavy) are not grey. However, since Statement 1 asserts that all fish are grey, this conclusion contradicts the first statement. Therefore, this conclusion is false.

### Step 3: Final Evaluation
- **Conclusion 1** is true because it logically follows from the statements.
- **Conclusion 2** is false because it contradicts the first statement.

### Final Answer
Only Conclusion 1 is valid.

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