Read the following statements and select the correct option
Statement 1 : The 4-chambered heart of birds is superior to the 4-chambered heart of crocodiles.
Statement 2 : Crocodilian heart retains both systemic arches that join, causing mixing of blood in the dorsal aorta while avian heart has lost left systemic arch.

Options

A. (a) Both statements 1 and 2 are correct
B. (b) Statement 1 is correct but statement 2 is incorrect
C. (c) 1 is incorrect but statement 2 is correct
D. (d) Both statements 1 and 2 are incorrect

Answer

To determine the correctness of the two statements regarding the hearts of birds and crocodiles, we will analyze each statement step by step.

### Step 1: Analyze Statement 1
**Statement 1**: "The 4-chambered heart of birds is superior to the 4-chambered heart of crocodiles."

- The heart of birds is indeed a 4-chambered heart, which allows for efficient separation of oxygenated and deoxygenated blood.
- However, the 4-chambered heart of crocodiles is more complex because it retains both systemic arches (the left and right aortic arches). This complexity allows crocodiles to have a more versatile circulatory system, especially for breathing underwater.
- Therefore, this statement is **incorrect** because the crocodilian heart is considered more advanced than the avian heart.

### Step 2: Analyze Statement 2
**Statement 2**: "Crocodilian heart retains both systemic arches that join, causing mixing of blood in the dorsal aorta while avian heart has lost the left systemic arch."

- It is true that the crocodilian heart has both systemic arches. These arches can join together, and this can lead to some mixing of blood in the dorsal aorta.
- However, the statement implies that this mixing is a disadvantage, while in fact, it allows crocodiles to manage their oxygen supply effectively when submerged.
- The avian heart, on the other hand, has lost the left systemic arch, which is correct.
- Despite the factual accuracy of some parts, the implication that this mixing is a negative feature makes the statement misleading. Thus, it can be considered **incorrect** in the context provided.

### Conclusion
Both statements are incorrect based on the analysis above.

### Final Answer
The correct option is **D**: Both statements one and two are incorrect.

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