Filiform apparatus is a characteristic feature of:

Options

A. Zygote
B. Suspensor
C. Egg
D. Synergid

Answer

### Step-by-Step Solution:

1. **Understanding the Embryo Sac**: The embryo sac is a crucial structure in flowering plants, containing several cells that play different roles in fertilization and development. It typically consists of seven cells and eight nuclei.

2. **Identifying the Cells in the Embryo Sac**: The embryo sac contains:
- Three antipodal cells located at the chalazal end.
- One egg cell and two synergids located at the micropylar end.
- A central cell that contains two polar nuclei.

3. **Focus on Synergids**: Among the cells present in the embryo sac, the synergids are of particular interest. They are located adjacent to the egg cell at the micropylar end.

4. **Defining Filiform Apparatus**: The filiform apparatus refers to the finger-like projections found on the synergids. These structures are essential for the fertilization process.

5. **Function of Filiform Apparatus**: The filiform apparatus serves two main functions:
- It guides the pollen tube towards the egg cell during fertilization.
- It helps in the absorption of nutrients from the nucellus and transfers them to the embryo sac.

6. **Conclusion**: Based on the information gathered, the filiform apparatus is a characteristic feature of the synergids in the embryo sac.

### Final Answer:
The filiform apparatus is a characteristic feature of **Synergids**.

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