The eggs of placental mammals are described as

Options

A. microlecithal
B. teloecithal
C. centrolecithal
D. alecithal

Answer

To answer the question "The eggs of placental mammals are described as," we will analyze the types of eggs based on the amount and distribution of yolk present in them.

### Step-by-Step Solution:

1. **Understanding Egg Types**:
- Eggs can be classified based on the amount of yolk they contain. The types include:
- **Alicetal**: No yolk.
- **Microlacetal**: Very little yolk.
- **Mesolacetal**: Moderate amount of yolk.
- **Polylacetal (or Macrolacetal)**: Enormous amount of yolk.

2. **Distribution of Yolk**:
- Eggs can also be classified based on the distribution of the yolk:
- **Homolacetal (or Isolacetal)**: Yolk is uniformly distributed throughout the egg.
- **Telolacetal**: Yolk is concentrated at one pole of the egg.
- **Centralacetal**: Yolk is concentrated at the center of the egg.

3. **Identifying Placental Mammals**:
- Placental mammals are also known as eutherian mammals.
- The type of egg associated with eutherian mammals is the **alicetal** type, which means they have no yolk.

4. **Conclusion**:
- Therefore, based on the classification of eggs and the specific characteristics of placental mammals, the answer to the question is that the eggs of placental mammals are described as **alicetal**.

### Final Answer:
The eggs of placental mammals are described as **alicetal**.