A clarifier or a word that describes a noun
A plural noun indicates that there is more than one of that noun (while a singular noun indicates that there is just one of the noun). ... Regular plurals follow this rule (and other similar rules), but irregular plurals are, well, not regular and don't follow a “standard” rule.
They were better off. Without the discovery of the uses of fire, mankind would not be here. Fire led to the rapid increase of newer, more advanced tech, such as a sword instead of a club.