After the removal of cancerous tumor by surgical procedure, the organ is treated with chemotherapy or radiotherapy. Explain the reason with reference to the concept of cell cycle

Explanation

### Step-by-Step Solution:

1. **Understanding Cancerous Tumors**: Cancerous tumors consist of cells that divide uncontrollably. This uncontrolled division is a result of mutations in the cell cycle regulation mechanisms, leading to rapid proliferation of cancer cells.

2. **Surgical Removal of Tumors**: When a cancerous tumor is surgically removed, it is important to note that not all cancer cells may be eliminated. Some cancer cells can remain in the surrounding tissue.

3. **Nutrient Supply to Remaining Cells**: After surgery, the remaining cancerous cells can still receive nutrients from the body. These cells are adept at attracting nutrients, which can promote their growth and division.

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