Chordates differ from non chordates in having

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding Chordates and Non-Chordates:**
- Chordates are a group of animals that possess certain key features during some stage of their development. Non-chordates are animals that do not have these features.

2. **Identifying Key Features of Chordates:**
- The three main characteristics that distinguish chordates from non-chordates are:
- **Notochord:** A flexible rod-like structure that provides support. Chordates have a notochord at some stage in their life cycle, while non-chordates do not.
- **Dorsal Hollow Nerve Cord:** In chordates, the nerve cord is located on the dorsal side (the back) and is hollow. In contrast, non-chordates typically have a ventral (belly side) solid nerve cord.
- **Pharyngeal Gill Slits:** These are openings in the pharynx that can develop into gills in aquatic chordates. They are present in chordates but absent in non-chordates.

3. **Evaluating the Options:**
- **Option A:** Notochord - Correct, as chordates have it, and non-chordates do not.
- **Option B:** Dorsal hollow nerve cord - Correct, as chordates have a dorsal hollow nerve cord, while non-chordates have a ventral solid nerve cord.
- **Option C:** Pharyngeal gill slits - Correct, as these are present in chordates and absent in non-chordates.
- **Option D:** All of the above - Since all the previous options are correct, this option is also correct.

4. **Conclusion:**
- Since all three features (notochord, dorsal hollow nerve cord, and pharyngeal gill slits) are present in chordates and absent in non-chordates, the correct answer is **Option D: All of the above.**