heart wood comprises dead elemetnns with highly (A)_____ walls and it does not conduct water &Minerals.

Answer

To answer the question regarding heartwood, we can break down the information step by step:

1. **Understanding Heartwood**: Heartwood is the central part of a tree trunk that is formed from older xylem tissue. It is typically darker in color compared to the surrounding sapwood.

2. **Composition of Heartwood**: Heartwood comprises dead elements. These are the older xylem cells that have lost their functionality over time.

3. **Characteristics of Heartwood**: The walls of the cells in heartwood are highly lignified. Lignin is a complex organic polymer that provides rigidity and strength to the cell walls.

4. **Functionality**: Due to the fact that heartwood is made up of dead cells, it does not conduct water and minerals. This is because the vascular system, which is responsible for the transport of water and nutrients, is not present in these dead cells.

5. **Final Answer**: Therefore, the blank in the statement can be filled with "lignified". The complete statement reads: "Heartwood comprises dead elements with highly (A) lignified walls and it does not conduct water & minerals."