Two auricles are separated by an _________in the heart of mammals.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Structure of the Heart**: The human heart consists of four chambers: two auricles (also known as atria) and two ventricles. The right auricle receives deoxygenated blood, while the left auricle receives oxygenated blood.

2. **Identifying the Separation of Auricles**: The question asks about the separation between the two auricles. In mammals, including humans, there is a specific structure that separates the right and left auricles.

3. **Naming the Structure**: The structure that separates the two auricles is called the "interauricular septum." The term "septum" refers to a wall or partition, "inter" means between, and "auricular" pertains to the auricles.

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