Framework element are

Options

A. 6
B. 4
C. 3
D. 2

Answer

### Step-by-Step Solution:

1. **Understanding Framework Elements**: Framework elements are the basic elements that provide structural support to biological molecules and cells. In the context of biology, these elements are crucial for forming the backbone of various organic compounds.

2. **Identifying Key Elements**: The primary framework elements in biological systems are carbon (C), hydrogen (H), and oxygen (O). These elements are fundamental in the formation of carbohydrates, proteins, lipids, and nucleic acids.

3. **Role of Each Element**:
- **Carbon (C)**: It is the central element in organic chemistry and forms the backbone of most biological molecules. Carbon can form four covalent bonds, allowing for complex structures.
- **Hydrogen (H)**: It is often found bonded to carbon and is essential in forming water and organic compounds.
- **Oxygen (O)**: This element is vital for respiration and is a part of many organic molecules, including carbohydrates and water.

4. **Conclusion on the Number of Framework Elements**: Based on the identification of these key elements, we conclude that there are three primary framework elements in biological systems: carbon, hydrogen, and oxygen.

5. **Final Answer**: Therefore, the correct answer to the question "Framework elements are" is **3**.