Which one of the following plants is dioecious?

Options

A. Cycas
B. Papaya
C. Marchantia
D. All of these

Answer

To determine which of the following plants is dioecious, we need to understand what dioecious means and then analyze the options provided.

### Step-by-Step Solution:

1. **Define Dioecious Plants**:
- Dioecious plants are those in which male and female reproductive organs are found on separate individuals. This means that one plant will produce only male flowers, while another will produce only female flowers.

2. **Identify the Plants in the Options**:
- We need to look at the plants provided in the options. The options mentioned are Cyclus, Papaya, and Marchantia.

3. **Analyze Each Plant**:
- **Cyclus**: This plant has male and female cones on separate plants, which qualifies it as dioecious.
- **Papaya**: The papaya plant also has male and female flowers on different individuals, making it strictly dioecious.
- **Marchantia**: This is a heterothallic species, meaning it has male and female reproductive structures on different individuals. Therefore, it is also considered dioecious.

4. **Conclusion**:
- Since all three plants (Cyclus, Papaya, and Marchantia) exhibit dioecious characteristics, the answer to the question is that all of these plants are dioecious.

### Final Answer:
All of these plants (Cyclus, Papaya, and Marchantia) are dioecious.

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