Vessels occur in
(a) All angiosperms, all gymnosperms, and some pteridophytes
(b) All angiosperms and some gymnosperms
(c) Most angiosperms, a few gymnosperms and pteridophytes
(d) All pteridophytes

Options

A. All angiosperms, all gymnosperms, and some pteridophytes
B. All angiosperms and some gymnospersm
C. Most angiosperms, a few gymnosperms and pteridophytes
D. All pteridophytes

Answer

To determine where vessels occur among different plant groups, we need to analyze the options provided in the question.

1. **Understanding Vessels**: Vessels are specialized structures found in the xylem of plants. They are responsible for the conduction of water and minerals. Vessels are primarily found in angiosperms (flowering plants).

2. **Analyzing the Options**:
- **Option (a)**: "All angiosperms, all gymnosperms, and some pteridophytes."
- This option is incorrect because vessels are not present in all gymnosperms. Some gymnosperms, particularly certain conifers, lack vessel elements.

- **Option (b)**: "All angiosperms and some gymnosperms."
- This option is partially correct, as vessels are indeed present in all angiosperms, but it does not account for the presence of vessels in pteridophytes.

- **Option (c)**: "Most angiosperms, a few gymnosperms and pteridophytes."
- This option is correct. Vessels are found in most angiosperms, some gymnosperms, and a few pteridophytes. This accurately reflects the distribution of vessels in these plant groups.

- **Option (d)**: "All pteridophytes."
- This option is incorrect because vessels are not present in pteridophytes; they primarily have tracheids for water conduction.

3. **Conclusion**: Based on the analysis, the correct answer is **(c) Most angiosperms, a few gymnosperms and pteridophytes**.