When you use a indefinite article you are referring of a class of people, places or things

The three of them 
 the defined ones are 
-el (singular male)
-los (pluaral male)
-la (singular female)
-las (plural female)
the indefinite ones are 
-un (sm)
-unos (pm)
-una (sf)
-unas(pf)
for example qou can say "un perro me mordió" or"una casa he visto ayer" or "una ricas manzanas" its for all three bc it is not defined what or who or were are you talking about
lol sorry for my english i´m latina s sorry 

Dis the correct answer

How would you describe enrique salaverria sculpture of a woman with a building raising up from her headthis is fairly subjective, but one way to describe enrique salaverría’s sculpture of a woman with a building raising up from her head would be "majestic" and "powerfulhope this < 3