The plural form of the noun 'bag' is bags.
Bags is the plural of bag, so bags is a plural noun.
Baggage is a plural form of bag.
The word 'reusable' is an adjective, a word that describes a singular or a plural noun. Adjectives don't have singular or plural forms, they have comparisons: reusable, more reusable, most reusable.Take the reusable bag to do your shopping.The coffee shop doesn't have reusable cups and plates.
The plural of zip is zips. As in "this bag has so many zips".
Bags is the plural of bag, so bags is a plural noun.
The word crises is a plural word; it is the plural form of the word crisis.
The noun 'bags' is the plural form of the singular noun 'bag', a common, concrete noun; a word for a type of flexible container, usually made of paper, plastic, cloth, or leather; a word for a thing.
The plural of nut is nuts. As in "I would like a bag of mixed fruit and nuts".
There is no plural word for if.
The plural word for delay is delays.
The plural form for the demonstrative pronoun this is these.
A non-plural word, a word (noun or pronoun) that is not plural is singular, a word for just one.