Which of the following pairs are correctly matched?
(1) Poikilothermous - Birds and mammals
(2) Agnath - Petromyzon and Myxine
(3) Tunicates - Ascidia, Salpa and Doliolum
(4) Cartilaginous fishes - Betta and Labeo

Options

A. 1 and 2
B. 1, 2 and 3
C. 2 and 3
D. 1, 2 and 4

Answer

To determine which pairs are correctly matched, we will analyze each option one by one:

1. **Poikilothermous - Birds and mammals**:
- Poikilothermous animals are those whose body temperature varies with the environment. Birds and mammals, however, are homeotherms (warm-blooded), meaning they maintain a constant body temperature regardless of environmental changes.
- **Conclusion**: This pair is **incorrect**.

2. **Agnath - Petromyzon and Myxine**:
- Agnatha is a class of jawless fish, which includes species such as Petromyzon (lampreys) and Myxine (hagfish).
- **Conclusion**: This pair is **correct**.

3. **Tunicates - Ascidia, Salpa, and Doliolum**:
- Tunicates are marine animals that belong to the subphylum Urochordata. Ascidia (sea squirts), Salpa, and Doliolum are all examples of tunicates.
- **Conclusion**: This pair is **correct**.

4. **Cartilaginous fishes - Betta and Labeo**:
- Cartilaginous fishes include sharks and rays, which have a skeleton made of cartilage. Betta (a type of freshwater fish) and Labeo (another freshwater fish) are actually bony fishes, not cartilaginous.
- **Conclusion**: This pair is **incorrect**.

Now, summarizing the correctness of the pairs:
- (1) Incorrect
- (2) Correct
- (3) Correct
- (4) Incorrect

Thus, the correctly matched pairs are (2) and (3).

### Final Answer:
The correct pairs are:
- (2) Agnath - Petromyzon and Myxine
- (3) Tunicates - Ascidia, Salpa, and Doliolum