Which is not formed by endoderm?

Options

A. Pancreas
B. Kidneys with cloaca
C. Liver
D. Lungs.

Answer

To determine which option is not formed by the endoderm, we can analyze each option based on their embryonic origins.

1. **Understanding the Germ Layers**:
- The three primary germ layers in embryonic development are ectoderm, mesoderm, and endoderm. Each layer gives rise to specific tissues and organs in the body.

2. **Identifying the Origin of Each Option**:
- **A. Pancreas**: The pancreas is derived from the endoderm. It develops from the foregut region during embryogenesis.
- **B. Kidneys with Cloaca**: The kidneys, including the cloaca, are derived from the mesoderm. They develop from the intermediate mesoderm.
- **C. Liver**: The liver is also derived from the endoderm, specifically from the foregut.
- **D. Lungs**: The lungs are formed from the endoderm as well, developing from the respiratory diverticulum.

3. **Conclusion**:
- Among the options given, the kidneys with cloaca (Option B) are the only ones that are not formed by the endoderm. Instead, they originate from the mesoderm.

Thus, the answer is **B. Kidneys with Cloaca**.

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