Which of the following is a chordate feature, not shared by the non-chordates?

Options

A. Triploblastic body
B. Truel coelom
C. Bilateral symmetry
D. Notochord

Answer

To determine which of the following is a chordate feature not shared by non-chordates, we will analyze each option provided:

1. **Triploblastic Body**:
- A triploblastic body is characterized by three germ layers: ectoderm, mesoderm, and endoderm.
- Both chordates and many non-chordates (like members of the phylum Platyhelminthes) possess a triploblastic body.
- Therefore, this feature is **not exclusive** to chordates.

2. **True Coelom**:
- A true coelom is a body cavity that is completely lined by mesoderm.
- This feature is present in many chordates as well as non-chordates, including coelomates like Annelida, Mollusca, and Arthropoda.
- Thus, this feature is also **not exclusive** to chordates.

3. **Bilateral Symmetry**:
- Bilateral symmetry refers to organisms that can be divided into two identical halves along one plane.
- This characteristic is found in both chordates and many non-chordates, such as Annelida and Arthropoda.
- Hence, this feature is **not exclusive** to chordates.

4. **Notochord**:
- The notochord is an embryonic structure that provides support and is a defining characteristic of all chordates.
- Non-chordates do not possess a notochord; it is exclusively found in the phylum Chordata.
- Therefore, the notochord is a feature that is **not shared by non-chordates**.

Based on this analysis, the correct answer is **Notochord**.