What is the most common and primitive type of ovule, respectively?

Options

A. circinotropous and campylotropous ovule
B. Amphitrophous and orthotropous ovule
C. Orthotropous and anatropous ovule
D. Anatropous and orthotropous ovule

Answer

To answer the question about the most common and primitive type of ovule, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Ovule Types**: Begin by identifying the different types of ovules. The main types include:
- Orthotropous
- Anatropous
- Campylotropous
- Amphitropous
- Circinotropous

2. **Defining Primitive and Common**:
- The term "primitive" refers to the simplest or earliest form in evolutionary terms.
- "Common" refers to the type of ovule that is most frequently found in various species.

3. **Evaluating Each Type**:
- **Orthotropous Ovule**: This type is characterized by a straight structure and is considered one of the simplest forms of ovule.
- **Anatropous Ovule**: This type shows a 180-degree rotation, making it more complex than the orthotropous but still widely found in angiosperms.
- **Campylotropous Ovule**: This type has a curved structure (about a 75-degree curve).
- **Amphitropous Ovule**: This type shows a 90-degree inversion.
- **Circinotropous Ovule**: This type has a long funicle and a circular structure, showing a complete 360-degree rotation.

4. **Identifying the Most Common and Primitive**:
- The **Orthotropous Ovule** is considered the most primitive due to its straight structure.
- The **Anatropous Ovule** is the most common type found in angiosperms, despite being more complex than the orthotropous.

5. **Final Answer**: Therefore, the most common and primitive types of ovules are:
- Most Common: **Anatropous Ovule**
- Most Primitive: **Orthotropous Ovule**

### Summary:
- The most common ovule is the **Anatropous Ovule**.
- The most primitive ovule is the **Orthotropous Ovule**.