Trunks of some of the aged tree species appear to be composed of several fused trunks. It it a physiological or anatomical abnormality ? Explain in detail.

Explanation

### Step-by-Step Solution:

1. **Understanding the Structure of Tree Trunks**:
- Tree trunks are primarily formed through a process called secondary growth, which is characteristic of dicotyledonous plants (dicots). This process involves the activity of the vascular cambium, a layer of meristematic tissue.

2. **Role of Vascular Cambium**:
- The vascular cambium is responsible for producing new cells. It generates new xylem (wood) cells towards the inside and new phloem (bark) cells towards the outside. This continuous cell division and differentiation lead to the thickening of the trunk over time.

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