The answer D best defines a cell.
True.
Precipitation is a water cycle process that happens when tiny droplets of liquid falls from the atmosphere it was settling. The hydrogen and oxygen mix back together and forms the water droplet altogether as it falls.
The water cycle involves other process from evaporation, condensation and precipitation.
The mechanisms responsible for specification of the dorsal axis include a post-fertilization cortical rotation that promotes a dorsal accumulation of β-catenin, and the activation of a cascade of regulatory genes by the complexes of β-catenin and HMG box transcription factors that start the process of gastrulation