The major portion of the dry weight of plants comprised of

Options

A. N, P, K
B. Ca, Mg, S
C. C, N, H
D. C, H, O

Answer

To solve the question regarding the major portion of the dry weight of plants, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Dry Weight**: The dry weight of a plant refers to the mass of the plant after all the water has been removed. This weight is primarily made up of various elements that contribute to the structure and function of the plant.

2. **Identifying Key Elements**: The question provides several options: nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, carbon, hydrogen, and oxygen. We need to identify which of these elements constitutes the major portion of the dry weight.

3. **Framework Elements**: The elements that primarily make up the structure of the plant are known as framework elements. These include carbon (C), hydrogen (H), and oxygen (O). They are essential for forming organic compounds and are integral to the plant's structure.

4. **Evaluating the Options**:
- **Option A (Nitrogen, Phosphorus, Potassium)**: While these are essential nutrients, they do not make up the major portion of dry weight.
- **Option B (Calcium, Magnesium, Sulfur)**: These are also important but are not the primary components of dry weight.
- **Option C (Carbon, Nitrogen, Hydrogen)**: This option includes nitrogen, which is not a major structural component.
- **Option D (Carbon, Hydrogen, Oxygen)**: This is the correct option as these three elements are the primary constituents of the dry weight of plants.

5. **Conclusion**: After evaluating all the options, we can conclude that the major portion of the dry weight of plants is comprised of carbon, hydrogen, and oxygen.

### Final Answer:
The major portion of the dry weight of plants is comprised of **Carbon, Hydrogen, and Oxygen** (Option D).

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