Who proved for the first time that the plants contains a large number of minerals and microelements?

Options

A. De saussure (1904)
B. Leibeg (1840)
C. Glauber and Mayhn (1650)
D. Arnon and stout (1939)

Answer

To answer the question of who first proved that plants contain a large number of minerals and microelements, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the individual who first demonstrated that plants contain a variety of minerals and microelements.

2. **Analyzing the Options**:
- **Option 1: D. Saucer**: This individual is known for his contributions to linguistic theory, which is unrelated to plant nutrition. Thus, he cannot be the correct answer.
- **Option 2: Liebig**: A German chemist known for his work in agricultural chemistry. Although he made significant contributions to the understanding of organic compounds and fertilizers, he did not specifically prove the presence of a large number of minerals and microelements in plants. Therefore, he is not the correct answer.
- **Option 3: Arnon and Stout**: They are known for establishing the criteria of essentiality for plant nutrients. They identified essential elements that plants require for growth and categorized them into macronutrients and micronutrients. Their work directly relates to the understanding of minerals and microelements in plants.

3. **Conclusion**: Based on the analysis of the options, the correct answer is **Arnon and Stout**, as they were the first to provide evidence and criteria regarding the essential minerals and microelements in plants.

### Final Answer:
**Arnon and Stout** proved for the first time that plants contain a large number of minerals and microelements.

---