Question

select the one word that makes up the complete predicate. both of these metal water bottles leak.

Explanation:

In the sentence "Both of these metal water bottles leak", the complete predicate consists of the verb and any objects, complements, or modifiers related to the verb. The verb here is "leak", which is the main part of the predicate showing the action of the subject ("Both of these metal water bottles"). So the word that makes up the complete predicate (in terms of the main verb) is "leak".

Answer:

leak