The sinus venosus and conus arteriosus in the heart of frog are present on which surface respectively 

Options

A. dorsal, lateral
B. ventral, lateral
C. dorsal and ventral
D. dorsal and lateral

Answer

To answer the question regarding the positions of the sinus venosus and conus arteriosus in the heart of a frog, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structures**:
- The **sinus venosus** is a chamber that collects deoxygenated blood from the body and is formed by the merging of the two precaval veins and one postcaval vein.
- The **conus arteriosus** is a structure that leads from the ventricle of the heart and helps in sending blood out to the lungs and body.

2. **Identify the Location of Sinus Venosus**:
- The sinus venosus is located **dorsally** (on the back side) of the heart. This is where it receives blood from the body.

3. **Identify the Location of Conus Arteriosus**:
- The conus arteriosus is located **ventrally** (on the front side) of the heart. It is positioned at the exit point of the ventricle.

4. **Match the Locations**:
- Based on the identified positions, we can conclude that the sinus venosus is on the dorsal surface and the conus arteriosus is on the ventral surface.

5. **Select the Correct Option**:
- Among the provided options, the correct answer is **dorsal and ventral** for the sinus venosus and conus arteriosus, respectively.

### Final Answer:
The sinus venosus and conus arteriosus in the heart of a frog are present on the **dorsal** and **ventral** surfaces, respectively.

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