Question

With decrease in temperature oxyhaemoglobin curve will become

Answer 1

Oxyhaemoglobin dissociation curve
A graph plotted to illustrate the percent oxyhaemoglobin saturation at different values of $p{O}_2$ (partial pressure of oxygen) is called the oxyhaemoglobin dissociation curve.
In normal conditions it is a sigmoid S-shaped curve.Effect of low temperature
At lower temperature, the affinity of haemoglobin towards oxygen is high and oxyhaemoglobin does not dissociate and haemoglobin remains saturated with oxygen.
Thus the curve shifts to the left and becomes more steep.