First of all who demosntrate that sunlight is essential for photosynthesis in plants.

Answer

**Step-by-Step Text Solution:**

1. **Understanding Photosynthesis**: Photosynthesis is the process by which plants convert light energy from the sun into chemical energy, specifically in the form of glucose. This process is essential for the growth and sustenance of plants.

2. **Role of Sunlight**: Sunlight provides the necessary light energy that is absorbed by plants to carry out photosynthesis. Without sunlight, the process cannot occur.

3. **Chlorophyll's Function**: The green pigment in plants, known as chlorophyll, plays a crucial role in absorbing sunlight. It is primarily found in the green parts of the plant, such as leaves.

4. **Chemical Equation of Photosynthesis**: During photosynthesis, plants convert carbon dioxide and water into glucose (C6H12O6) and oxygen, using sunlight as the energy source.

5. **Historical Contribution**: The first person to demonstrate that sunlight is essential for photosynthesis was Jan Ingenhousz. He conducted experiments that showed the necessity of light for the process of photosynthesis.

6. **Biographical Information**: Jan Ingenhousz was born on December 8, 1730, and passed away on September 7, 1799. His work laid the foundation for our understanding of photosynthesis.