Prototheria or subclass of egg laying mammals is connected with

Options

A. Kangaroo
B. Echidna
C. Ornithorhyncus
D. Both B and C .

Answer

To solve the question regarding Prototheria, or the subclass of egg-laying mammals, we need to analyze the options provided and understand the classification of mammals.

### Step-by-Step Solution:

1. **Understand the Classification of Mammals**:
- Mammals are classified into two main subclasses: Prototheria and Theria.
- Prototheria includes egg-laying mammals, while Theria includes live-bearing mammals.

2. **Identify the Characteristics of Prototheria**:
- Prototheria consists of mammals that lay eggs, known as oviparous mammals.
- The order within Prototheria is called Monotremata, which includes species like the duck-billed platypus and the echidna (spiny anteater).

3. **Evaluate the Options**:
- **Kangaroo**: This is a marsupial and belongs to the subclass Theria, specifically the infraclass Metatheria. Therefore, it does not belong to Prototheria.
- **Echidna**: This is a type of monotreme and is indeed an egg-laying mammal. It falls under Prototheria.
- **Ornithorhynchus**: This is the scientific name for the duck-billed platypus, which is also an egg-laying mammal and belongs to Prototheria.

4. **Conclusion**:
- Since both the echidna and the duck-billed platypus are part of Prototheria, the correct answer to the question is "both B and C".

### Final Answer:
The subclass of egg-laying mammals, Prototheria, is connected with both echidna and ornithorhynchus (duck-billed platypus).

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