The anomaly of tooth number is mostly due to hereditary factors.

遗传因素对牙齿数目异常起主导作用。

Influence factors of rice quality were formulated such as hereditary factors, environmental factor and agricultural measure factor.

综述了品种特性（遗传）、自然环境和农艺措施等因素对稻米品质的影响。

Smoking is so detrimental to the entire human system that it alone causes more illnesses than all the other environmental or hereditary factors put together.

抽烟对人体危害如此之大以至于单其本身引起的疾病数目就超过了一切其它环境、遗传因素引起疾病数的总和。