Frogs and toads belong to anura or salientia whose characteristic feature is

Options

A. Absence of postanal tail
B. Distinct tympanum
C. No trace of external gills and gill slits in adults
D. All of these

Answer

**Step-by-Step Solution:**

1. **Identify the Class:** Frogs and toads belong to the class Amphibia, specifically to the order Anura (or Salientia).

2. **Characteristic Feature:** The defining characteristic of Anura is the absence of a tail in adult forms. This is a key feature that distinguishes them from other amphibians.

3. **Absence of External Structures:** In addition to the absence of a tail, Anura also lacks external gills and gill slits in their adult stage. While their larvae (tadpoles) have gills for respiration, adults breathe through lungs and skin.

4. **Hearing Mechanism:** Anura possess a structure known as the tympanum, which is a small external ear structure that helps in hearing. Unlike humans, they do not have an external ear (pinna), and sound enters through this tympanic membrane.

5. **Conclusion:** Therefore, the characteristic features of frogs and toads (Anura) include the absence of a tail, no external gills or gill slits in adults, and the presence of a tympanum for hearing.

6. **Final Answer:** The correct characteristic feature of frogs and toads belonging to Anura is the absence of a tail in adults, along with other features such as the tympanum and the lack of external gills.

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