糖在水中的溶解达到饱和点时，晶体的成核过程就会开始。

When sugar reaches its saturation point in water, the ___nucleation of crystals begins.

水蒸气凝结成雨滴的第一步是成核过程。

The first step in water vapor forming raindrops is the ___nucleation process.

在珍珠形成过程中，异物周围会通过成核作用逐渐沉积矿物质。

In pearl formation, minerals gradually deposit around foreign objects through the process of ___nucleation.