Common trait among reptiles, fishes and amphibia is -

Options

A. Gill
B. Scales
C. Laying eggs
D. Shelled

Answer

**Step-by-Step Solution:**

1. **Identify the Groups**: We need to analyze the common traits among reptiles, fishes, and amphibians. These are three distinct groups of animals within the animal kingdom.

2. **Examine the Options**: The options provided are:
- A) Gills
- B) Scales
- C) Laying eggs
- D) Shells

3. **Analyze Each Option**:
- **Gills**: Gills are respiratory organs primarily found in fish. While amphibians have gills during their larval stage, reptiles do not have gills at any stage. Therefore, this option is not common among all three groups.
- **Scales**: Scales are present in reptiles and fish, but amphibians typically do not have scales. Thus, this option is also not common among all three groups.
- **Laying Eggs**: All three groups—reptiles, fishes, and amphibians—are oviparous, meaning they lay eggs. This is a common trait among them.
- **Shells**: Shells are not present in fish and are only found in some reptiles (like turtles), but not in amphibians. Therefore, this option is incorrect as well.

4. **Conclusion**: After analyzing all the options, the only common trait among reptiles, fishes, and amphibians is that they all lay eggs.

Thus, the correct answer is **C) Laying eggs**.

---