地里庄稼出现叶黄、株矮、生长迟缓等症状，需施加复合肥。下列物质属于复合肥的是(  )

下列有关太阳的说法，正确的是（　　）

①在△ABC中，若sinA＞sinB，则必有cosA＜cosB；

②在△ABC中，若a，b，c成等比数列，则角B的取值范围为 $(0,\frac{\pi }{3}$ ；

③等比数列{a_n}中，若a₃=2，a₇=8，则a₅=±4；

④等差数列{a_n}的前n项和为S_n，S₁₀＜0且S₁₁=0，满足S_n≥S_k对n∈N^*恒成立，则正整数k构成集合为{5，6}

⑤若关于x的不等式（a²﹣1）x²﹣（a﹣1）x﹣1＜0的解集为R，则a的取值范围为 $\left(-\frac{3}{5},1\right)$ ．

其中正确结论的序号是____．（填上所有正确结论的序号）．

    2014 is the year of horse in China. Do you know anything about the horse?

    The horse is strong and runs very fast. He's a useful and hard-working animal. The horse learns to know his owner soon. He loves his owner, even after his owner loses his life. Here's a story about such a horse. In a war, the owner passed away(死), and fell from his horse. When people found his body some days later, the horse was still standing beside it. During that long time, the horse didn't leave the body of his owner, without food or water, in the coldest weather, driving away the birds that might eat it. Wasn't he a great animal?