参考答案

正确答案：abilities
abilities 解析：空前的with以及空后that引导的定语从句表明，本空应填一名词(短语)。题干中的People lacking determination与该句提到的People who lack grit对应，usually与more often than not对应，they are not born with与they just don't have the innate对应，that引导的定语从句successful people have为原文信息复现，故文中successful people have的先行词abilities即为本题答案。