When temperature decrease, oxy-Hb curve becomes

Options

A. more steep
B. straight
C. parabola
D. none of these

Explanation

### Step-by-Step Solution:

1. **Understanding the Oxygen-Hemoglobin Curve**: The oxygen-hemoglobin dissociation curve illustrates how hemoglobin's oxygen saturation changes with varying partial pressures of oxygen. It is typically sigmoid in shape.

2. **Identifying the Effect of Temperature**: The question asks about the effect of a decrease in temperature on the oxygen-hemoglobin curve. It is important to know that temperature is one of the factors that influence hemoglobin's affinity for oxygen.

3. **Recognizing the Shift in the Curve**: When the temperature decreases, the affinity of hemoglobin for oxygen increases. This means that hemoglobin is more likely to bind to oxygen at lower temperatures.

4. **Direction of the Shift**: A decrease in temperature causes the oxygen-hemoglobin curve to shift to the left. This leftward shift indicates that at a given partial pressure of oxygen, hemoglobin is more saturated with oxygen compared to higher temperatures.

5. **Conclusion**: Since the curve becomes steeper with a leftward shift, we conclude that when the temperature decreases, the oxygen-hemoglobin curve becomes "more steep."

6. **Final Answer**: The correct option is **A. More steep**.