Type of placenta present in humans/rodents is

Options

A. Discoidal
B. Zonary
C. Difuse
D. Cotyledonary.

Answer

### Step-by-Step Text Solution:

1. **Understanding the Question**: The question asks about the type of placenta present in humans and rodents.

2. **Definition of Placenta**: The placenta is a vital organ that forms during pregnancy, facilitating the exchange of nutrients, gases, and waste between the mother and the developing fetus.

3. **Types of Placenta**: There are several types of placentas classified based on their structure and how they connect to the fetus. The main types include:
- Discoidal
- Zonary
- Diffuse
- Cotyledonary

4. **Discoidal Placenta**:
- The discoidal placenta is characterized by a disc-shaped area of attachment to the fetus.
- In this type, the chorion forms a cylindrical structure that connects to the fetus at a single point.
- This type of placenta is found in humans, rodents, and most primates.

5. **Other Types of Placenta**:
- **Zonary Placenta**: This type surrounds the fetus like a belt and is found in carnivores such as cats and dogs.
- **Diffuse Placenta**: Here, the entire chorion is involved in forming villi that cover the fetus, seen in horses and pigs.
- **Cotyledonary Placenta**: In this type, the chorion connects to the fetus at multiple points called cotyledons, found in ruminants.

6. **Conclusion**: Based on the characteristics and examples provided, the type of placenta present in humans and rodents is the **discoidal type**.