在命题“若抛物线$y=a{x}^2+bx+c$的开口向下，则$\left\{x|a{x}^2+bx+c<0\right\}\ne \varnothing$”的逆命题、否命题、逆否命题中结论成立的是（   ）

    Hello, I'm Lily. I have a friend. Her name's Sally. She's eleven. Her birthday is on 10th July. She lives far from school. She goes to school by bus. Her favourite colour is red. She has a red hat. She can read and write. She is good at writing. She wants to be a teacher in the future. She wants to teach Chinese in a school.

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生态系统的说法中错误的是（    ）