Final answer:
The mature stage of a thunderstorm is predominantly characterized by downdrafts, heavy rain, strong winds, and severe weather phenomena such as lightning and thunder.
Step-by-step explanation:
In the life cycle of a thunderstorm, the mature stage is characterized predominantly by downdrafts.
The mature stage of a thunderstorm is the stage when the storm is at its strongest and most intense. This is when the updrafts and downdrafts within the storm are well-developed.
During this stage, there is a continuous supply of warm air rising in the updrafts, while cool air descends in the downdrafts. These downdrafts can cause heavy rain, strong winds, and even hail. The mature stage is often associated with severe weather phenomena, such as lightning and thunder.