The question may appear like this question, however here I doubt the plurality of the second noun
What is correct, and what is the difference of
English Language Learners Stack Exchange is a question and answer site for speakers of other languages learning English. It only takes a minute to sign up.Sign up to join this community
This suggests that all of the elements are in the same position. And it is looking for the positions at includes all of the elements.
This is a single element in one position.
This is multiple elements in multiple positions.
These positions are for a single element
These positions are for multiple elements
This position is for an element.
This position is for multiple elements.