Which of the following is not a general characteristic of phylum Chordata ?

Options

A. Vertebral column
B. Dorsal, hollow nerve cord
C. Notochord
D. Pharyngeal slits

Explanation

To determine which of the following is not a general characteristic of phylum Chordata, we need to analyze the options given:

1. **Identify the characteristics of Chordata**: The phylum Chordata is defined by four main characteristics that must be present at some stage in the life cycle of all chordates:
- Notochord
- Dorsal hollow nerve cord
- Pharyngeal gill slits
- Postanal tail

2. **Examine each option**:
- **Option A: Vertebral column**: This is a characteristic of vertebrates, a subphylum of Chordata, but it is not present in all chordates. For example, urochordates and cephalochordates do not have a vertebral column.
- **Option B: Dorsal hollow nerve cord**: This is a defining feature of all chordates, present in all subphyla.
- **Option C: Notochord**: This is also a defining feature of all chordates, present at least during embryonic stages in all members of the phylum.
- **Option D: Pharyngeal gill slits**: These are present in all chordates at some stage of their life cycle.

3. **Conclusion**: Since the vertebral column is not a characteristic found in all chordates (it is specific to vertebrates), the correct answer to the question "Which of the following is not a general characteristic of phylum Chordata?" is **Option A: Vertebral column**.

### Summary of Steps:
1. Identify the general characteristics of Chordata.
2. Analyze each option to see if it fits the definition of a characteristic present in all chordates.
3. Conclude that the vertebral column is not a characteristic of all chordates.