一个机械缺陷导致了飞机坠毁。

A mechanical ___defect caused the plane to crash.

遗传缺陷可以通过早期筛查检测出来。

Genetic ___defects can be detected through early screening.

肥胖可能由潜在的遗传缺陷引起。

Obesity may result from underlying genetic ___defects.