Which of the following options contains a set of protochordates ?

Options

A. Balaenoptera , Macropus , Salpa
B. Delphinus , Columba , Doliolum
C. Doliolum , Ascidia , Saccoglossus
D. Salpa , Doliolum, Branchiostoma

Answer

To determine which option contains a set of protochordates, we need to analyze each option carefully. Protochordates are a group of animals that include the subphyla Urochordata and Cephalochordata.

### Step-by-Step Solution:

1. **Identify the Options**: We have four options to analyze:
- Option 1: Balenoptera, Macropus, Salpa
- Option 2: Delphinus, Columba, Doliolum
- Option 3: Doliolum, Acedia, Sarcoglossus
- Option 4: Salpa, Doliolum, Branchiostoma

2. **Analyze Option 1**:
- Balenoptera (a genus of baleen whales) and Macropus (a genus of kangaroos) are both chordates but not protochordates.
- Salpa is a protochordate (Urochordata).
- Conclusion: This option does not contain a complete set of protochordates.

3. **Analyze Option 2**:
- Delphinus (dolphin) and Columba (pigeon) are both chordates but not protochordates.
- Doliolum is a protochordate (Urochordata).
- Conclusion: This option does not contain a complete set of protochordates.

4. **Analyze Option 3**:
- Doliolum is a protochordate (Urochordata).
- Acedia (also known as ascidians) is also a protochordate (Urochordata).
- Sarcoglossus is a hemichordate, not a protochordate.
- Conclusion: This option does not contain a complete set of protochordates.

5. **Analyze Option 4**:
- Salpa is a protochordate (Urochordata).
- Doliolum is also a protochordate (Urochordata).
- Branchiostoma (amphioxus) is a protochordate (Cephalochordata).
- Conclusion: This option contains a complete set of protochordates.

6. **Final Answer**: The correct answer is **Option 4: Salpa, Doliolum, and Branchiostoma**.