State the difference between the first trophic levels of detritus food chain and grazing food chain.

Explanation

### Step-by-Step Solution:

1. **Definition of Trophic Levels**:
- Trophic levels refer to the position an organism occupies in a food chain, which is determined by its feeding relationships.

2. **First Trophic Level in Grazing Food Chain**:
- In the grazing food chain, the first trophic level is occupied by **producers** (autotrophs), such as plants and phytoplankton.
- These producers convert **radiant energy** (sunlight) into **chemical energy** through the process of photosynthesis.
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