Which of the following is used for long term energy storage by animals

Options

A. Glucose
B. Amino acids
C. Glycogen
D. Fat

Answer

To answer the question "Which of the following is used for long term energy storage by animals?" we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding the Options**:
- The options given are glucose, amino acids, glycogen, and fat. We need to determine which of these is primarily used for long-term energy storage in animals.

2. **Analyzing Glucose**:
- Glucose is a simple carbohydrate and serves as an immediate source of energy for cellular respiration. It is not stored for long-term energy; instead, it is quickly utilized for energy needs.
- **Conclusion**: Glucose is not used for long-term energy storage.

3. **Analyzing Amino Acids**:
- Amino acids are the building blocks of proteins. They are primarily used for protein synthesis and other metabolic functions rather than energy storage. When amino acids are in excess, they are not stored as energy but are converted into other compounds.
- **Conclusion**: Amino acids are not used for long-term energy storage.

4. **Analyzing Glycogen**:
- Glycogen is a polysaccharide that serves as a form of energy storage in animals. It is primarily stored in the liver and muscles and can be quickly converted back to glucose when energy is needed. However, glycogen is not considered a long-term energy storage molecule, as it can be depleted relatively quickly during periods of fasting or intense exercise.
- **Conclusion**: Glycogen is an energy storage molecule but not a long-term storage option.

5. **Analyzing Fats**:
- Fats (or lipids) are the primary form of long-term energy storage in animals. They are stored in adipose tissue and can be mobilized when the body requires energy over an extended period. Fats provide a dense source of energy and are utilized during prolonged periods without food.
- **Conclusion**: Fats are indeed used for long-term energy storage in animals.

### Final Answer:
The correct answer is **fat**.

---