[填空题]
An iron cube floats in asa*3dcx0bu/tt* .zn sdbtr nk) el;z-x hn1*+ a+*kxk bowl of liquid mercury at 0$^{\circ} $C. (a) If the temperature is raised to 25$^{\circ} $C, will the cube float higher or lower in the mercury?
(b) By what percent will the fraction of volume submerged change? %