Glomerular filtration rate (GFR) and transport maximum (Tm).

Explanation

### Step-by-Step Text Solution:

1. **Understanding the Terms**:
- The question asks for definitions of two important concepts in renal physiology: Glomerular Filtration Rate (GFR) and Transport Maximum (Tm).

2. **Definition of Glomerular Filtration Rate (GFR)**:
- GFR is defined as the volume of filtrate produced by the kidneys per minute. Specifically, it refers to the amount of blood plasma that is filtered through the glomeruli (the tiny filters in the kidneys) each minute.
- It is a crucial indicator of kidney function and is typically measured in milliliters per minute (mL/min).
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