Darius is learning the names of two or three new objects or events every day. This rapid increase in vocabulary is referred to as the explosion

Naming

Explanation:

Naming explosion-

A sudden increase in an infant’s vocabulary, especially in the number of nouns, that begins at about 18 months of age. Between 12 and 18 months, almost every infant learns the name of each significant caregiver and sibling (and sometimes each pet). Initially children use just a few names, mostly for familiar things and people. But when they are still just beginning to talk, many babies will suddenly start naming everything and asking for the names of everything they see.

Naming Explosion

Explanation:

Naming explosion is the process in which a child learn to add new words to his vocabulary.

It is usually a stage in language development which children undergo and it usually occurred at their 2 year of age leading to increase in their spoken words because they learn the name of two or more objects on a daily basis which in turn give them a sound and clear vocabulary.

the factors that the economies of the muslim empires prosper were:

1- land trade routes-located between three continents  

2- sea trade routes

trade contributed to the spread of muslim empires, and with that islamic culture led to a growing feeling of internationalism resulted in the transfer of technology, science, and other cultural forms.