Show with the help of a sketch that the plants are the ultimate source of food.

Explanation

### Step-by-Step Text Solution

**Step 1: Introduction to Plants as Autotrophs**
- Begin by explaining that plants are known as autotrophs. Autotrophs are organisms that can produce their own food using simple substances.

**Step 2: The Process of Photosynthesis**
- Describe the process of photosynthesis, which is how plants create their food. Explain that during photosynthesis, plants use sunlight to convert carbon dioxide (from the atmosphere) and water (from the soil) into glucose (a type of carbohydrate) and oxygen.

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