Otolith is formed of

Options

A. carbohydrate
B. Magnesium
C. Lipid
D. Calcium carbonate

Answer

### Step-by-Step Solution:

1. **Understanding the Term "Otolith":**
- Otoliths are small structures located in the inner ear of vertebrates, commonly referred to as "ear stones."

2. **Identifying Alternative Names:**
- Otoliths are also known as statoliths or autoconium. This helps in understanding their function and location.

3. **Composition of Otoliths:**
- Otoliths are primarily composed of crystals. The specific type of crystal that makes up otoliths is crucial for answering the question.

4. **Analyzing the Options:**
- The options provided are:
- A) Carbohydrates
- B) Magnesium
- C) Lipid
- D) Calcium Carbonate
- We need to evaluate each option based on the composition of otoliths.

5. **Evaluating Each Option:**
- **A) Carbohydrates:** These are biomolecules, but otoliths are not made of carbohydrates. This option is incorrect.
- **B) Magnesium:** While magnesium is a mineral, otoliths are not composed of magnesium salts. This option is incorrect.
- **C) Lipid:** Lipids are fatty acids and do not make up otoliths. This option is incorrect.
- **D) Calcium Carbonate:** This is the correct composition of otoliths. They are indeed made of calcium carbonate crystals.

6. **Conclusion:**
- Based on the analysis, the correct answer is **D) Calcium Carbonate**.