Mixing of oxygenated and deoxygenated blood occurs in the heart of

Options

A. Bird
B. Crocodile
C. Rabbit
D. Frog

Answer

To answer the question "Mixing of oxygenated and deoxygenated blood occurs in the heart of", we can follow these steps:

### Step 1: Understand the Structure of the Heart
- The heart is a muscular organ that pumps blood throughout the body. It consists of chambers: atria (upper chambers) and ventricles (lower chambers).

### Step 2: Identify Types of Circulation
- There are two types of circulation:
- **Single Circulation**: Blood passes through the heart once in a complete cycle (seen in fish).
- **Double Circulation**: Blood passes through the heart twice (seen in mammals, birds, and some reptiles).

### Step 3: Analyze the Heart Structure in Different Animals
- **Mammals**: Have a four-chambered heart (two atria and two ventricles). Oxygenated and deoxygenated blood do not mix.
- **Birds**: Also have a four-chambered heart, preventing the mixing of blood.
- **Reptiles**: Generally have a three-chambered heart, which can lead to some mixing of blood, except for crocodiles which have a four-chambered heart.
- **Amphibians (e.g., Frogs)**: Typically have a three-chambered heart, which allows for mixing of oxygenated and deoxygenated blood.

### Step 4: Identify the Correct Answer
- Among the options given (bird, crocodile, rabbit, frog), the only animal where mixing of oxygenated and deoxygenated blood occurs in the heart is the **frog** (an amphibian).

### Conclusion
- The correct answer is **frog**.

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