Final answer:
Duality of levels in human language enhances communication and helps ensure the survival and well-being of individuals and communities.
Step-by-step explanation:
Duality of levels is one of the economical features of human language because it allows for the efficient encoding and sharing of specific information about the environment. This feature enables humans to distinguish between different categories or types of objects or phenomena and communicate that distinction to others. For example, if there are venomous and non-venomous snakes in an area, having separate words for each type of snake allows people to alert each other to the presence of a dangerous one. Duality of levels in language enhances communication and helps ensure the survival and well-being of individuals and communities.