Why is wood made up of xylem and not of phloem?

Explanation

### Step-by-Step Solution:

1. **Understanding Wood Composition**: Wood is primarily composed of xylem tissue, which is formed during the secondary growth of plants.

2. **Role of Vascular Cambium**: The vascular cambium is a layer of meristematic tissue that facilitates the growth of xylem and phloem. It is located between the xylem (inner side) and phloem (outer side).

3. **Secondary Growth**: During secondary growth, the vascular cambium produces secondary xylem towards the inside and secondary phloem towards the outside.

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