Introduction:
The process of photosynthesis occurs in the leaves of plants, where they use sunlight, water, and carbon dioxide to produce food. The food produced in the leaves is in the form of starch, which is a complex carbohydrate. Starch is a storage form of glucose that can be broken down later to provide energy for the plant.

Explanation:
1. Photosynthesis:
Photosynthesis is the process by which plants convert sunlight, water, and carbon dioxide into glucose and oxygen. It takes place in the chloroplasts of plant cells, particularly in the leaves. Chloroplasts contain a pigment called chlorophyll, which gives plants their green color and is essential for photosynthesis.

2. Sunlight absorption:
Chlorophyll molecules in the chloroplasts absorb sunlight energy. This energy is used to convert carbon dioxide and water into glucose and oxygen. The light-dependent reactions occur in the thylakoid membranes of the chloroplasts, while the light-independent reactions (Calvin cycle) occur in the stroma.

3. Glucose production:
During photosynthesis, the energy from sunlight is used to split water molecules into hydrogen and oxygen. The hydrogen atoms combine with carbon dioxide to form glucose (C6H12O6) in a series of chemical reactions. Glucose is a simple sugar that serves as the primary source of energy for the plant.

4. Storage as starch:
Plants produce more glucose than they immediately need for energy. Excess glucose is converted into starch, a polysaccharide made up of many glucose molecules joined together. Starch is insoluble in water and can be stored within the cells of the plant, particularly in storage organs like tubers, bulbs, and seeds.

5. Why starch is the main food produced:
Starch is an ideal form of storage for plants because it is compact, insoluble, and can be broken down easily when needed. It can be hydrolyzed into glucose molecules, which can then be used for respiration or transported to other parts of the plant for growth and development.

Conclusion:
In conclusion, the food produced in the leaves of plants is primarily in the form of starch. This starch is a storage form of glucose and allows plants to store excess energy for future use. Starch provides a readily available source of energy when required and is an essential component of the plant's overall metabolism.