Which of the following is not a fundamental character of a chordate?

Options

A. Rod like soild structure Notochord present dorsally.
B. Solid , ventral and double nerve cord
C. Paired Pharyngeal gill slits
D. Heart is ventral in all

Answer

To determine which of the following is not a fundamental character of a chordate, we need to analyze each option based on the defining characteristics of chordates. Chordates are characterized by the presence of:

1. Notochord
2. Dorsal hollow nerve cord
3. Pharyngeal slits
4. Post-anal tail
5. Endostyle or thyroid gland

Now, let's evaluate each option:

1. **Rod-like solid structure notochord present dorsally**: This is a fundamental character of chordates. The notochord is indeed a defining feature, so this option is **not** the correct answer.

2. **Solid ventral and double nerve cord**: This statement is incorrect for chordates. Chordates have a dorsal hollow nerve cord, not a solid ventral one. This option is the correct answer as it does not represent a fundamental character of chordates.

3. **Paired pharyngeal gill slits**: This is also a fundamental character of chordates. These structures are present in the embryonic stage of chordates, so this option is **not** the correct answer.

4. **Heart is ventral in all**: This statement is true for many chordates, particularly vertebrates, but it is not a universal characteristic of all chordates. However, it does not disqualify it as a fundamental character since it applies to a significant group within chordates.

Based on this analysis, the option that is not a fundamental character of a chordate is:

**Answer: Solid ventral and double nerve cord.**