Final answer:
The firmest wax proposed for feature restoration and deep filling of large cavities is known as amalgam.
Step-by-step explanation:
The firmest wax proposed for feature restoration and the deep filling of large cavities is known as amalgam. Amalgam is a type of dental material used by dentists to treat cavities. It is a solid solution composed of 50% mercury and 50% of a powder containing silver, tin, copper, zinc, and mercury.