Central region -clogged secondary xylem is
(a) central wood
(b) heartwood
(c) alburnum
(d) hardwood

Options

A. central wood
B. heartwood
C. alburnum
D. hardwood

Answer

To answer the question about which term describes the central region with clogged secondary xylem, we can analyze each option step by step:

1. **Understanding the Question**: The question asks for the term that refers to the central region of a plant where the secondary xylem is clogged. This indicates that we are looking for a specific type of wood.

2. **Analyzing the Options**:
- **(a) Central Wood**: This term is not commonly used in botanical terminology. It does not specifically refer to clogged secondary xylem, so we can eliminate this option.

- **(b) Heartwood**: Heartwood, also known as duramen, is the central part of a tree that is typically darker and consists of dead cells. This region is characterized by clogged secondary xylem due to the accumulation of various substances like resins and tannins. Heartwood does not conduct water but provides structural support. This option seems promising.

- **(c) Alburnum**: Alburnum, also known as sapwood, is the outer part of the secondary xylem that is still active in conducting water. It does not have clogged xylem, so this option can be eliminated.

- **(d) Hardwood**: Hardwood is a general term that refers to wood from angiosperms. While it can include heartwood, it does not specifically denote clogged secondary xylem. Therefore, this option is not the best choice.

3. **Conclusion**: Based on the analysis, the correct answer is **(b) heartwood**, as it specifically refers to the central region of a tree where the secondary xylem is clogged.