Siphonozoids of Pennatula differ from autozooids in

Options

A. Having tentacles and gonads
B. Lacking mesenteries
C. Lacking tentacles and gonads
D. Having mesenteries.

Answer

To answer the question regarding how siphonozoids of Pennatula differ from autozooids, we can follow these steps:

### Step 1: Understand the Structure of Pennatula
Pennatula, commonly known as the sea pen, is a colonial organism that consists of two types of zooids: autozooids and siphonozoids.

### Step 2: Identify the Characteristics of Autozooids
Autozooids are the feeding zooids of Pennatula. They are typically located along the upper margin of the rachis (the central axis of the colony) and possess tentacles and gonads, which are essential for feeding and reproduction.

### Step 3: Identify the Characteristics of Siphonozoids
Siphonozoids, on the other hand, are specialized zooids that are found on the dorsal and lateral sides of the colony. They are primarily involved in maintaining water currents through the colony and do not have tentacles or gonads.

### Step 4: Compare the Two Types of Zooids
- **Autozooids**: Have tentacles and gonads, located along the upper margin of the rachis.
- **Siphonozoids**: Lack tentacles and gonads, located on the dorsal and lateral sides, and have reduced mesenteries.

### Step 5: Determine the Correct Answer
Based on the characteristics identified, the siphonozoids of Pennatula differ from autozooids in that they **lack tentacles and gonads**.

### Conclusion
The correct answer to the question is: **Siphonozoids of Pennatula differ from autozooids in lacking tentacles and gonads.**

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