noun
variability; mutability
Abstract noun describing the quality of being changeable or mutable; used in technical, scientific, or formal contexts.
このシステムの可変性が高いため、様々な状況に対応できる。
Because this system has high variability, it can handle various situations.
遺伝子の可変性は進化の原動
Genetic variability is one of the driving forces of evolution.
不変性 means 'invariability' or 'immutability', the opposite of 可変性.
Compound of 可変 (kahen, 'variable') + 性 (-sei, '-ity, -ness'). The exact historical derivation is uncertain, but the kanji 可変 is a Sino-Japanese word meaning 'changeable'.