A:The less; the healthier
B:The less; the more healthier
C:The more; the healthier
D:The more; the more healthier
(Ⅰ)求证:直线PA与PB的斜率乘积为定值;
(Ⅱ)设点M,N在椭圆C上,O为坐标原点,当OM∥PA,ON∥PB时,求△OMN的面积.
如图表示某植物叶片所处的状态,图中所表示的是该叶片正在进行( )