Oxygen Dissocaition curve is normally sigmoid/parabolic.

Explanation

### Step-by-Step Solution:

1. **Understanding the Oxygen Dissociation Curve**:
- The oxygen dissociation curve illustrates the relationship between the partial pressure of oxygen (pO2) and the percentage saturation of hemoglobin with oxygen.

2. **Shape of the Curve**:
- The curve is typically described as sigmoid (S-shaped). This shape indicates that hemoglobin's affinity for oxygen increases as more oxygen molecules bind to it.

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