Which of the following characters is shared by all chordates at some stage of life ?

Options

A. Notochord
B. Dorsal tubular nerve cord
C. Pharyngeal gill slits
D. All of the above

Answer

To solve the question regarding which character is shared by all chordates at some stage of life, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Characteristics of Chordates**:
- Chordates are defined by four main characteristics at some stage of their life cycle:
- **Notochord**: A flexible rod that provides support.
- **Dorsal tubular nerve chord**: A nerve cord located along the back.
- **Pharyngeal gill slits**: Openings in the throat area that may develop into gills in aquatic species.
- **Post-anal tail**: An extension of the body past the anal opening.

2. **Analyze the Options**:
- **Option A: Notochord** - This is indeed a characteristic of all chordates.
- **Option B: Dorsal tubular nerve chord** - This is also a characteristic found in all chordates.
- **Option C: Pharyngeal gill slits** - These are present in all chordates during some stage of development.
- **Option D: All of the above** - Since all the previous options (A, B, and C) are characteristics of chordates, this option must be correct.

3. **Conclusion**:
- Since all the options (notochord, dorsal tubular nerve chord, and pharyngeal gill slits) are shared by all chordates at some stage of their life, the correct answer is **Option D: all of the above**.

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