State True or false :
Carbon is an essential element in the molecule on which life is based but silicon is only satisfactory.

Explanation

To determine whether the statement "Carbon is an essential element in the molecule on which life is based but silicon is only satisfactory" is true or false, we can analyze the roles of both carbon and silicon in biological systems.

### Step-by-Step Solution:

1. **Understanding the Role of Carbon**:
- Carbon is a fundamental element in organic chemistry and is the backbone of all known life forms. It can form stable bonds with a variety of elements, including itself, hydrogen, oxygen, nitrogen, and sulfur.
- Carbon atoms can form long chains and complex ring structures, which are essential for the formation of biomolecules such as carbohydrates, proteins, lipids, and nucleic acids.

2. **Examining the Role of Silicon**:
- Silicon, while it shares some chemical similarities with carbon, does not form stable compounds in the same way. The silicon-silicon bonds are generally less stable compared to carbon-carbon bonds due to silicon's larger atomic size.
- Silicon does not readily form the complex chains and rings that are necessary for the structures of biomolecules. Therefore, while silicon can form some compounds, it is not as versatile or stable as carbon in biological contexts.

3. **Conclusion**:
- Given that carbon is essential for life and forms a wide variety of stable and complex molecules, while silicon is only satisfactory and does not fulfill the same role, we conclude that the statement is **True**.

### Final Answer:
The statement is **True**.

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