physiological gradient

例句：

1. 1. The physiological gradient between the two species is significant.
   两种物种之间的生理梯度是显著的。
2. 2. The study of physiological gradients has important implications for understanding evolution.
   研究生理梯度对理解进化具有重要意义。
3. 3.The physiological gradient in the brain is responsible for many cognitive functions.
   大脑中的生理梯度负责许多认知功能。