Osmotically inactive chief stored material in animal body is

Options

A. Protein
B. Phosphogen
C. Lipid
D. Glycogen.

Answer

To answer the question "Osmotically inactive chief stored material in animal body is," we will analyze the options provided and determine which one fits the criteria of being osmotically inactive and a chief storage material in animals.

### Step-by-Step Solution:

1. **Understanding Osmotic Activity**:
- Osmotic activity refers to the ability of a substance to affect the movement of water across a semipermeable membrane. Osmotically active substances can draw water into or out of cells, potentially disrupting osmotic balance.

2. **Identifying Storage Materials**:
- The question asks for the chief stored material in the animal body that is osmotically inactive. We need to evaluate each option provided.

3. **Evaluating the Options**:
- **A. Protein**:
- Proteins are primarily building blocks of tissues and not typically stored as energy reserves. They are not classified as chief storage materials. Therefore, this option is incorrect.
- **B. Phosphagen**:
- Phosphagens, such as ATP and creatine phosphate, are high-energy molecules used for immediate energy needs, not for long-term storage. Thus, this option is also incorrect.
- **C. Lipid**:
- Lipids (fats) serve as energy storage but are not the chief storage material in animals. They are also not osmotically inactive since they can affect osmotic balance. This option is incorrect.
- **D. Glycogen**:
- Glycogen is a polysaccharide that serves as the primary storage form of glucose in animals. It is stored mainly in the liver and muscles. Glycogen is osmotically inactive because it is insoluble in water and does not significantly affect osmotic balance. Therefore, this option is correct.

4. **Conclusion**:
- The correct answer to the question is **Glycogen** (Option D), as it is the chief stored material in the animal body that is osmotically inactive.

### Final Answer:
**Glycogen**