Bipedalism - walking on two feet - is one of the defining characteristics of being human, and scientists have debated for years how it came about.
Bipedalism - walking on two feet - is one of the defining characteristics of being human, and scientists have debated for years how it came about.
用两条腿走路是人类的基本特征之一，多年来，科学家们在这一特征的形成问题上一直争论不休。