________ are the chemical messengers that are secreted into the blood directly.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the Question**: The question asks for the name of the chemical messengers that are secreted directly into the blood.

2. **Identifying the Chemical Messengers**: The chemical messengers that fit this description are known as hormones.

3. **Function of Hormones**: Hormones act as chemical messengers because they carry information or instructions from one set of cells to another, facilitating communication within the body.

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