An organism which lacks sterile covering over its zygote is

Options

A. Yeast
B. Funaria
C. Riccia
D. Cycas.

Answer

To solve the question "An organism which lacks sterile covering over its zygote is," we will analyze the given options step by step.

### Step-by-Step Solution:

1. **Understanding the Question**:
The question asks for an organism that does not have a sterile covering over its zygote. In biology, a zygote is the initial cell formed when two gametes (sperm and egg) fuse during fertilization.

2. **Analyzing the Options**:
The options given are:
- A) Yeast
- B) Cunaria
- C) Rixia
- D) Cyclus

3. **Evaluating Each Option**:
- **Option A: Yeast**:
Yeast is a eukaryotic fungus that reproduces both sexually and asexually. In its sexual reproduction, it forms a zygote, which does not have a sterile covering. Therefore, this option is a potential answer.

- **Option B: Cunaria**:
Cunaria is a type of plant. In plants, zygotes typically have a sterile covering, so this option is incorrect.

- **Option C: Rixia**:
Rixia is also a plant, and like Cunaria, it has a sterile covering over its zygote. Thus, this option is also incorrect.

- **Option D: Cyclus**:
Cyclus is another plant that possesses a sterile covering over its zygote, making this option incorrect as well.

4. **Conclusion**:
After evaluating all options, the only organism that lacks a sterile covering over its zygote is **Yeast**. Therefore, the correct answer is **A) Yeast**.

### Final Answer:
The organism which lacks sterile covering over its zygote is **Yeast**.

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