题目

All of the following are the themes of The Call of the Wild, EXCEPT _____. A . everyone must be bold to face reality in a gesture to make a living. B . the love between humans and animals deserves to be highly praised. C . human beings are supposed to live in harmony with all kinds of creatures. D . it is not the strongest of the species that survive, but the one that must be responsive to changes.如图，抛物线y1=（x+1）2+1与y2=a（x﹣4）2﹣3交于点A（1，3），过点A作x轴的平行线，分别交两条抛物线于B、C两点，且D、E分别为顶点．则下列结论：①a=；②AC=AE；③△ABD是等腰直角三角形；④当x＞1时，y1＞y2.其中正确结论的个数是（　 　）A. 1个 B. 2个 C. 3个 D. 4个