This means they rise because of mental disarray or discriminatory thoughts.
Explanation:
Psychological and cognitive both mean having to do with the brain. All biases are because of the thought of oneself having better or worse qualities than a certain person or group of people. (i.e. Men thinking they're superior to women, South Africans believing they are better than those from Togo, etc.)
The muscularis externa layer has three layers of muscle. An innner oblique layer , a middle circular and an external longitudinal layer. The contraction of these muscle layers help to break up the food mechanically.
