What is true

Options

A. Diatoms produce basidiospores
B. Heterocysts occur in Nostoc
C. Fronds develop in bryophytes
D. Multiciliate sperms occur in angiosperms.

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks which statement is true among the provided options related to various biological concepts.

2. **Analyzing Each Option**:
- **Option 1**: "Diatoms produce vasodious pores."
- **Analysis**: This statement is incorrect because diatoms do not produce vasodious pores.
- **Option 2**: "Hydrocytes occur in no-stock."
- **Analysis**: This statement is correct. Hydrocytes are specialized cells found in certain plants, particularly in the context of nitrogen fixation.
- **Option 3**: "Prunes develop in bryophytes."
- **Analysis**: This statement is incorrect. Prunes are dried plums and do not develop in bryophytes.
- **Option 4**: "Multicellular springs occur in angiosperms."
- **Analysis**: This statement is also incorrect. The term "springs" is not typically associated with angiosperms in this context.

3. **Identifying the Correct Option**: After analyzing all options, the only true statement is that hydrocytes occur in no-stock, which is related to their role in nitrogen fixation.

4. **Conclusion**: The correct answer is that hydrocytes occur in no-stock, as they help create anaerobic conditions necessary for the functioning of nitrogen-fixing enzymes.