The hormone which increases alertness pupillary dilation , piloerection is chemically:

Options

A. Peptide hormone
B. Steroid hormone
C. lodothyronine
D. Amino acid derivation

Answer

To solve the question regarding the hormone that increases alertness, pupillary dilation, and piloerection, we can analyze the options provided step by step.

### Step-by-Step Solution:

1. **Understanding the Question**:
- We need to identify a hormone that is responsible for increasing alertness, causing pupillary dilation, and inducing piloerection (the contraction of hair muscles causing hair to stand up).

2. **Analyzing the Options**:
- **Option 1: Peptide Hormone**:
- Peptide hormones are involved in various physiological functions such as growth, appetite regulation, and energy metabolism. They do not primarily increase alertness or cause pupillary dilation and piloerection.
- **Conclusion**: This option is incorrect.

- **Option 2: Steroid Hormone**:
- Steroid hormones are primarily involved in controlling metabolism, immune function, and sexual characteristics. They do not specifically increase alertness or cause the physiological responses mentioned in the question.
- **Conclusion**: This option is also incorrect.

- **Option 3: Idothyronine**:
- Idothyronine (thyroid hormone) plays a significant role in metabolic processes, heart function, brain development, and bone maintenance. However, it does not directly relate to alertness or the other responses mentioned.
- **Conclusion**: This option is incorrect.

- **Option 4: Amino Acid Derivative**:
- Amino acid derivatives, such as catecholamines (e.g., adrenaline), are known to increase alertness, cause pupillary dilation, and induce piloerection. These hormones are released during the 'fight or flight' response and are responsible for the physiological changes associated with increased alertness.
- **Conclusion**: This option is correct.

3. **Final Answer**:
- The hormone that increases alertness, pupillary dilation, and piloerection is an **Amino Acid Derivative**.