A grazing food chain always starts with :

Options

A. Respiration
B. Decomposition
C. Photosynthesis
D. Nitrogen fixation

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks what a grazing food chain always starts with. We need to identify the correct process that initiates this type of food chain.

2. **Defining a Food Chain**: A food chain is a linear sequence that shows how energy and matter are transferred from one organism to another. It consists of producers, consumers, and decomposers.

3. **Types of Food Chains**: There are two main types of food chains:
- **Grazing Food Chain**: This type begins with producers, which are typically green plants or autotrophs that can produce their own food.
- **Detritus Food Chain**: This starts with dead organic matter and involves decomposers.

4. **Identifying Producers**: In a grazing food chain, the first level consists of producers. These producers utilize the process of photosynthesis to create energy-rich organic compounds from sunlight, carbon dioxide, and water.

5. **Evaluating the Options**:
- **Respiration**: This is a process by which organisms convert glucose and oxygen into energy, but it does not initiate the food chain.
- **Decomposition**: This refers to the breakdown of dead organic matter, which is not the starting point for a grazing food chain.
- **Photosynthesis**: This is the correct process that producers use to create food, thus starting the grazing food chain.
- **Nitrogen Fixation**: This is a process where certain organisms convert atmospheric nitrogen into a usable form, but it does not start a food chain.

6. **Conclusion**: The grazing food chain always starts with the process of photosynthesis, as it is the means by which producers create the energy necessary for the food chain to begin.

### Final Answer:
The grazing food chain always starts with **Photosynthesis**.

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