What is the source of the energy that flows through the living world?

Options

A. Photosynthesis
B. Respiration
C. Sun
D. ATP

Explanation

**Step-by-Step Solution:**

1. **Understanding Energy Flow in the Living World:**
- The energy flow in the living world refers to how energy is transferred from one organism to another within an ecosystem.

2. **Identifying the Categories of Organisms:**
- Organisms can be classified into three main categories:
- **Producers:** These are typically plants that produce their own food through photosynthesis.
- **Consumers:** These include primary consumers (herbivores) and top consumers (carnivores).

3. **Role of Producers:**
- Producers, such as plants, utilize sunlight to perform photosynthesis. The general equation for photosynthesis is:
\[ 6 \text{CO}_2 + 12 \text{H}_2\text{O} + \text{sunlight} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6 \text{O}_2 + 6 \text{H}_2\text{O} \]
- In this process, plants convert carbon dioxide and water into glucose and oxygen, using sunlight as the energy source.

4. **Importance of Sunlight:**
- Sunlight is the ultimate source of energy for all living organisms. It is captured by chlorophyll in plants, which then converts it into chemical energy during photosynthesis.

5. **Energy Transfer to Consumers:**
- The energy stored in glucose (produced by plants) is then transferred to primary consumers (herbivores) when they eat the plants.
- Primary consumers are then consumed by secondary consumers (carnivores), continuing the flow of energy through the food chain.

6. **Conclusion:**
- The ultimate source of energy that flows through the living world is the **sun**. This energy is harnessed by producers and subsequently transferred through various levels of consumers.