Fill in the blanks :
Cuboidal ……………… of collecting tubule is permeable to ………………… impermeable to salts.

Explanation

**Step-by-Step Solution:**

1. **Identify the Structure**: The question refers to the structure of the collecting tubule in the kidneys. The collecting tubule is lined with a specific type of epithelial tissue.

2. **Determine the Type of Epithelium**: The epithelial tissue that lines the collecting tubule is cuboidal in shape. Therefore, the first blank should be filled with "epithelium".

3. **Understand Permeability**: The question states that this cuboidal structure is permeable to a certain substance and impermeable to salts.

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