What do hard wood and soft wood stand for?

Explanation

**Step-by-Step Solution:**

1. **Definition of Hardwood and Softwood**: Hardwood and softwood refer to two different types of wood derived from different types of trees. Hardwood comes from angiosperms (flowering plants), while softwood comes from gymnosperms (non-flowering plants).

2. **Composition of Hardwood**: Hardwood is primarily composed of vessels and tracheids, which are types of xylem elements. These structures are responsible for the conduction of water and minerals within the plant.

3. **Characteristics of Hardwood**: The presence of vessels and a high lignin content in hardwood contributes to its density and hardness. Lignin is a complex organic polymer that strengthens cell walls, making hardwoods generally tougher and more durable.

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