Which one of the following is applicable to collision-coalescence process of precipitation?

The collision-coalescence process, also known as the 'warm-rain process', is the primary mechanism for precipitation in clouds that do not extend beyond the freezing level [1]. In these 'warm clouds', temperatures remain above 0°C throughout, meaning ice crystals cannot form. Instead, larger cloud droplets fall faster than smaller ones, colliding and merging (coalescing) with them to grow into raindrops [1]. This process is particularly dominant in tropical regions where the freezing level is high and clouds are often entirely composed of liquid water. While it can occur in the lower, warmer layers of clouds that do extend above the freezing level, the term is specifically applicable to the mechanism governing non-glaciated clouds where the Bergeron (ice-crystal) process is absent.

Sources

1. [1] https://www.nature.com/articles/s43247-023-00884-5