In maize grain, scutellum represents :

Options

A. endosperm
B. a shield-shaped cotyledon
C. protective covering of the radicle
D. protective covering of the plumule

Explanation

### Step-by-Step Solution:

1. **Understanding the Structure of Maize Grain**:
- Maize grain consists of several parts, including the endosperm, cotyledons, and protective coverings for the radical and plumule.

2. **Identifying the Scutellum**:
- The scutellum is a specialized structure found in the seeds of certain plants, including maize. It is a modified cotyledon.

3. **Function of the Scutellum**:
- The primary function of the scutellum is to absorb nutrients from the endosperm during the germination process. It is thin and has a large surface area to facilitate this absorption.

4. **Analyzing the Options**:
- **Endosperm**: This is the tissue that provides nourishment to the developing embryo but is not the same as the scutellum.
- **Shield-shaped Cotyledon**: This accurately describes the scutellum, as it is shaped like a shield and serves as the cotyledon in maize.
- **Protective Covering of the Radical**: This is known as the coleorhiza, not the scutellum.
- **Protective Covering of the Plumule**: This is referred to as the coleoptile, which is also not the scutellum.

5. **Conclusion**:
- Based on the analysis, the correct answer is that the scutellum represents a shield-shaped cotyledon.

### Final Answer:
The scutellum in maize grain represents a **shield-shaped cotyledon**.

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