Which of the following statement is correct?

Options

A. Amphibians evolved into reptiles.
B. Fish with stout and strong fins could move on land and go back to water. This was about 350 mya.
C. Giant ferns were present but they all fell to form coal deposits slowly.
D. all of these

Answer

To determine which statement is correct, we will analyze each statement provided in the question step by step.

### Step 1: Analyze the first statement
**Statement:** Amphibians evolved into reptiles.

**Analysis:**
- Evolution is a gradual process where species change over time.
- It is widely accepted that amphibians did evolve from fish and later gave rise to reptiles.
- This is supported by fossil records and evolutionary biology, indicating that amphibians developed adaptations that allowed them to transition to reptiles.

**Conclusion:** This statement is correct.

### Step 2: Analyze the second statement
**Statement:** Fish with stout and strong fins could move on land and go back to water around 350 million years ago.

**Analysis:**
- The evolution of lobe-finned fishes is believed to have occurred around 350 million years ago.
- These fish had adaptations that allowed them to venture onto land, which is a significant step in the evolution of amphibians.
- This statement aligns with the scientific understanding of evolutionary history.

**Conclusion:** This statement is also correct.

### Step 3: Analyze the third statement
**Statement:** Giant ferns were present but they all fell to the cold deposit slowly.

**Analysis:**
- During certain geological periods, giant ferns (pteridophytes) were indeed dominant plant forms on Earth.
- Over time, many of these plants died and contributed to coal deposits, which is a well-documented process in paleobotany.
- This statement reflects the historical dominance of ferns and their eventual contribution to coal formation.

**Conclusion:** This statement is correct as well.

### Final Conclusion
After analyzing all three statements, we find that:
- All statements provided in the question are correct. Therefore, the correct answer is that all of the statements are true.

### Answer:
**All of the statements are true.**

---