In the heart of frog, the ventricles open into

Options

A. sinus venosus
B. conus arteriosus
C. truncus arteriosus
D. pericardium

Answer

**Step-by-Step Solution:**

1. **Understand the Structure of the Frog's Heart:**
- The heart of a frog consists of three chambers: two atria and one ventricle. Unlike mammals, frogs have a single ventricle.

2. **Identify the Function of the Ventricle:**
- The ventricle is responsible for pumping blood out of the heart. In frogs, this ventricle is crucial for directing blood to both the lungs and the rest of the body.

3. **Know the Pathway of Blood Flow:**
- Blood from the ventricle does not directly enter the arteries. Instead, it first moves into a specific structure that helps in directing the blood flow.

4. **Identify the Structure that Connects the Ventricle to the Arteries:**
- The blood from the ventricle opens into a muscular structure called the Conus Arteriosus. This structure plays a vital role in directing blood to the correct arterial branches.

5. **Conclusion:**
- Therefore, in the heart of a frog, the ventricles open into the Conus Arteriosus, which then leads to the arterial branches.

**Final Answer:**
The ventricles of the frog's heart open into the Conus Arteriosus.

---