behaviour 这个词可数吗

So the working class child’s _________(behave), which they and their parents see as “respectful,” could impair their success in the classroom, and prevent them from joining their classmates in higher social classes.

答案给的是 behaviour  。

可是查字典：

[U] 行为；举止；态度 the way that sb behaves, especially towards other people

good/bad behaviour 

良好 / 恶劣行为

social/sexual/criminal behaviour 

社会 / 性 / 犯罪行为

His behaviour towards her was becoming more and more aggressive.

他对待她的态度越来越蛮横。

所以是答案错了吗?