A preformed nonalterable cranioplasty plate is a de- vice that is implanted in a patient to repair a skull defect and is constructed of a material, e.g., stainless steel or vitallium, that cannot be altered or reshaped at the time of surgery without changing the chemical behavior of the material.
Source: wiktionary
The students who are less successful describe themselves as helpless and atrtribute their unsuccessful outcomes to nonalterable and/or external causes such as stupidity, task difficulty, luck, poor teachers, or even bad days.
Source: wiktionary
Nonalterable variables are things we cannot change, such as ethnicity, socioeconomic status, gender, and home background.
Source: wiktionary