variation of black level

例句：

1. 1. The temperature variation is due to the altitude.
   温度的变化是由于海拔引起的。
2. 2. The genetic variation in this species is significant.
   这种物种的遗传变异是显著的。
3. 3.The researcher found that the population variation was not random.
   研究者发现人口变异不是随机的。