Embryo sac is to ovule as_________is to an anther.

Options

A. stamen
B. filament
C. pollen grain
D. androecium

Explanation

To solve the analogy "Embryo sac is to ovule as _______ is to anther," we need to understand the relationship between the components involved.

### Step-by-Step Solution:

1. **Understand the Components:**
- The **embryo sac** is a structure found within the **ovule**. It is the female gametophyte that contains the female gamete (egg cell).
- The **anther** is part of the male reproductive structure of a flower and is responsible for producing pollen.

2. **Identify the Equivalent Structures:**
- In the ovule, the embryo sac is the structure that houses the female gamete.
- In the anther, the equivalent structure that houses the male gamete is the **pollen grain**.

3. **Define the Terms:**
- The **embryo sac** is the female gametophyte.
- The **pollen grain** is the male gametophyte, which develops from the pollen mother cells located in the microsporangium of the anther.

4. **Establish the Relationship:**
- Just as the embryo sac is contained within the ovule, the pollen grain is produced within the anther. Therefore, the relationship is that both the embryo sac and the pollen grain are gametophytes, with the former being female and the latter being male.

5. **Fill in the Blank:**
- The correct answer to the analogy is **pollen grain**. Thus, the complete analogy reads: "Embryo sac is to ovule as pollen grain is to anther."

### Final Answer:
Embryo sac is to ovule as **pollen grain** is to anther.

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