Which of the following statements is incorrect about the frog ?
(i) Eyes are bulged out and covered by a nictitating membrane that protects them while in water
(ii) On either side of the eyes a membranous tympanum (ear) receives sound signals
(iii) The hind limbs end in four digits and they are largerr and muscular then force limbs that end in five digits
(iv) Frogs exhibit sexual dimorphism.

Options

A. (i) and (v)
B. (iii) only
C. (ii) and (iii)
D. (iv) only

Explanation

To determine which statement about frogs is incorrect, let's analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement (i)**: "Eyes are bulged out and covered by a nictitating membrane that protects them while in water."
- **Analysis**: This statement is true. Frogs have a nictitating membrane, which is a third eyelid that helps protect their eyes when they are submerged in water.

2. **Statement (ii)**: "On either side of the eyes, a membranous tympanum (ear) receives sound signals."
- **Analysis**: This statement is also true. The tympanum, or eardrum, is located on either side of the frog's head and is responsible for detecting sound waves.

3. **Statement (iii)**: "The hind limbs end in four digits and they are larger and muscular than forelimbs that end in five digits."
- **Analysis**: This statement is incorrect. Frogs have hind limbs that typically end in five digits, while their forelimbs end in four digits. The hind limbs are indeed larger and more muscular than the forelimbs, but the number of digits mentioned in the statement is wrong.

4. **Statement (iv)**: "Frogs exhibit sexual dimorphism."
- **Analysis**: This statement is true. Frogs do show sexual dimorphism, where males and females can be distinguished by size, coloration, and other physical characteristics.

### Conclusion:
The incorrect statement about frogs is **Statement (iii)**: "The hind limbs end in four digits and they are larger and muscular than forelimbs that end in five digits."

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