Which of the following is an adaptation to a terrestrial way of Life in the snail ?

Options

A. Using the mantle instead of gills for respiration
B. Cephalization with antennae and eyes
C. Hatchet foot for crawling
D. Torsion so that anus is above the head

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for an adaptation that allows snails to live on land (terrestrial life).

2. **Analyzing the Options**:
- **Option 1**: Using the mantle instead of gills for respiration.
- Snails have adapted to breathe air using their mantle, which functions similarly to a lung. This adaptation is crucial for their survival on land.
- **Option 2**: Cephalization with antennae and eyes.
- While cephalization (the development of a head with sensory organs) is important for many organisms, it is not specifically an adaptation for terrestrial life in snails.
- **Option 3**: Hatchet foot for crawling.
- The hatchet foot is a feature that helps snails move but is not specifically an adaptation for living on land.
- **Option 4**: Torsion so that anus is above the head.
- Torsion is a developmental process in snails but does not directly relate to their adaptation for terrestrial living.

3. **Identifying the Correct Option**:
- The correct adaptation for terrestrial life in snails is **Option 1**: using the mantle instead of gills for respiration. This adaptation allows snails to extract oxygen from the air, which is essential for their survival on land.

4. **Explanation of the Correct Adaptation**:
- The mantle in terrestrial snails has evolved to function as a lung (often referred to as the pallial lung), allowing them to breathe air directly. The mantle wall is vascularized, meaning it has a rich supply of blood vessels, which facilitates gas exchange. This adaptation is critical because traditional gills are ineffective in air.

**Final Answer**: The adaptation to a terrestrial way of life in snails is using the mantle instead of gills for respiration.

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