A researcher conducts a survey to understand public opinion on a newly implemented policy. The survey results indicate that 70% of respondents support the policy. However, the researcher later discovers that the survey was primarily distributed through an online platform that is mainly used by a specific demographic group that is known to be more likely to support the policy. What is the most significant limitation of this survey's findings?

设函数f(x)在[a,b]上二阶可导且f''(x)>0。若存在x₀∈(a,b)使得f'(x₀)=0，则下列哪个结论必然成立？

当个体发现自己在内心存在一个评判性的声音时，根据所给信息，以下哪种处理方式被认为是最有效的，且能帮助个体识别并摆脱这种声音的控制？

在Java中，给定以下代码片段： `int[] data = new int[5];` 和 `data[2] = 10;` 。如果紧接着执行 `int[] newData = data; newData[2] = 20;`，此时 `data[2]` 的值将是：

在Java中，以下哪种形式允许监听器类以外部类的形式独立存在？