List some of the plants are given below :-
Cedrus, Pinus, Cycas, Marchantia, Castor, Polytrichum, Mustard.
How many above plants have an independent free living existance of male and female gametophyte ?

Options

A. Three
B. Two
C. Five
D. Four

Answer

To determine how many of the listed plants have an independent free-living existence of male and female gametophytes, we need to analyze each plant type based on their reproductive structures.

### Step-by-Step Solution:

1. **Understanding Plant Types**:
- The plants listed are Cedrus (Cedar), Pinus (Pine), Cycas, Marchantia, Castor, Polytrichum, and Mustard.
- These plants can be categorized into three main groups: Gymnosperms, Angiosperms, and Bryophytes.

2. **Identifying Gymnosperms**:
- **Cedrus, Pinus, and Cycas** are Gymnosperms.
- In Gymnosperms, the male and female gametophytes are not free-living; they are dependent on the sporophyte for nutrition and support. The gametophytes are reduced and found within the cones.

3. **Identifying Angiosperms**:
- **Castor and Mustard** are Angiosperms.
- Similar to Gymnosperms, in Angiosperms, the male and female gametophytes (pollen grains and ovules) are also not free-living; they develop within the flowers and are dependent on the sporophyte.

4. **Identifying Bryophytes**:
- **Marchantia and Polytrichum** are Bryophytes.
- In Bryophytes, the gametophyte is the dominant stage and is independent and free-living. The male and female gametophytes exist separately and can live independently of the sporophyte.

5. **Conclusion**:
- From the analysis, only **Marchantia and Polytrichum** have independent free-living male and female gametophytes.
- Therefore, the answer is **2**.

### Final Answer:
**2 plants (Marchantia and Polytrichum) have an independent free-living existence of male and female gametophytes.**