Select the correct statement regarding reproduction.

Options

A. Mating in dogs in synchronised with lunar cycle
B. Salamanders always have internal fertilization
C. In Trygon, the male introduces sperms into female through a modified pelvic fin
D. Catla has internal fertilization

Answer

To solve the question regarding which statement about reproduction is correct, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Evaluate Option 1: Mating in dogs is synchronized with the lunar cycle.**
- The lunar cycle refers to the phases of the moon and its effects on various biological processes. While some animals may exhibit behaviors influenced by lunar cycles, it is not a general rule that mating in dogs is synchronized with this cycle.
- **Conclusion:** This statement is **incorrect**.

2. **Evaluate Option 2: Salamanders always have internal fertilization.**
- Salamanders are amphibians, and while many species do have internal fertilization, there are families of salamanders that utilize external fertilization. Thus, it is not accurate to say that all salamanders have internal fertilization.
- **Conclusion:** This statement is **incorrect**.

3. **Evaluate Option 3: In Trigon, the male introduces sperm into the female through a modified pelvic fin.**
- The Trigon, or stingray, has a unique reproductive method where males use modified pelvic fins called claspers to transfer sperm to the female. This is a well-documented reproductive behavior in this group of fish.
- **Conclusion:** This statement is **correct**.

4. **Evaluate Option 4: Catla has internal fertilization.**
- Catla is a freshwater fish known for its external fertilization process, where eggs are released into the water and fertilized by the male gametes. Therefore, stating that Catla has internal fertilization is incorrect.
- **Conclusion:** This statement is **incorrect**.

### Final Conclusion:
The only correct statement regarding reproduction is **Option 3: In Trigon, the male introduces sperm into the female through a modified pelvic fin.**

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