degenerative

长期吸烟会导致肺部发生退行性病变。

Long-term smoking can cause ___degenerative changes in the lungs.

阿尔茨海默病是一种退行性脑部疾病，会导致记忆逐渐丧失。

Alzheimer's is a ___degenerative brain disease that causes gradual memory loss.