Prochordates lack

Options

A. Cranium and vertebral column
B. Jaws and vertebral column
C. Paired appendages
D. All of the above

Answer

To answer the question "Prochordates lack," we need to analyze the characteristics of prochordates and the options provided.

### Step-by-Step Solution:

1. **Understand Prochordates**: Prochordates are informal groups of animals that share some characteristics with chordates but do not possess all the defining features of true chordates.

2. **Identify Key Characteristics of Prochordates**:
- Prochordates possess pharyngeal gill slits.
- They have a dorsal nerve cord.
- They lack a vertebral column (backbone).
- They also lack paired appendages (like limbs).

3. **Examine the Options**:
- **Option A**: Cranium and vertebral column - Prochordates do lack a vertebral column, but they do not necessarily lack a cranium as some may have a rudimentary structure.
- **Option B**: Jaws and vertebral column - Prochordates do lack jaws and a vertebral column.
- **Option C**: Paired appendages - Prochordates indeed lack paired appendages.
- **Option D**: All of the above - This option suggests that prochordates lack all the features mentioned in A, B, and C.

4. **Conclusion**: Since prochordates lack a vertebral column, jaws, and paired appendages, the correct answer is **D. All of the above**.

### Final Answer:
Prochordates lack **D. All of the above**.

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