Microlecithal eggs are found in :-

Options

A. Reptilia + Aves
B. Amphibia + Aves + Reptilia
C. Reptilia + Aves + Chiroptera
D. Eutheria

Answer

### Step-by-Step Solution:

1. **Understanding Microlecithal Eggs**: Microlecithal eggs are characterized by having very little yolk. This type of egg is typically found in certain groups of animals.

2. **Analyzing the Options**: The question provides several options regarding where microlecithal eggs can be found. We need to evaluate each option to determine if it contains microlecithal eggs.

3. **Evaluating Option 1 (Reptilia + Apes)**: Reptiles and apes generally have mesolecithal eggs, which contain a moderate amount of yolk. Therefore, this option is incorrect.

4. **Evaluating Option 2 (Amphibia + Apes + Reptilia)**: Amphibians, like reptiles and apes, also have mesolecithal eggs. Thus, this option is also incorrect.

5. **Evaluating Option 3 (Reptilia + Apes + Pteroptera)**: Similar to the previous options, reptiles and apes have mesolecithal eggs. This option is incorrect as well.

6. **Evaluating Option 4 (Eutheria)**: Eutherians, or placental mammals, are characterized by having microlecithal eggs. These eggs have very little or no yolk at all. This makes option 4 the correct answer.

7. **Conclusion**: Based on the evaluation, the correct answer to the question "Microlecithal eggs are found in:" is **Eutheria**.

### Final Answer:
Microlecithal eggs are found in **Eutheria** (option 4).

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