名詞 retrogression:

1. passing from a more complex to a simpler biological form
   同義詞：degeneration
2. returning to a former state
   同義詞：regression, regress, reversion, retroversion

ret.ro.gres.sion

n.（名詞）
The act or process of deteriorating or declining.
惡化：變?cè)愕幕蛩〉男袨榛蜻^(guò)程
Biology A return to a less complex or more primitive state or stage.
【生物學(xué)】 退化：向不太復(fù)雜的或更原始的狀態(tài)或階段的回歸