Hello! The word "that" is the determiner indicating the connection between "his uncle's thoughts/opinions" and "working for the government is the key to stability". These two parts of the sentences are not complete when separated. A conjunction would be a word connecting two different clauses like "but", "although", "however", "because". For example: I am very tired "but" I will still stay up to watch the movie with you. The word "but" joins the two clauses "I am very tired" and "I will still stay up to watch the movie with you" together. These clauses would also be complete sentences without the conjunction "but" joining them like this: "I am very tired." "I will still stay up to watch the movie with you." I hope that helps!

His uncle thinks that working for the government is the key to stability. His uncle - subject thinks - verb that working for the government is the key to stability - object [noun clause] that - subordinating conjunction working for the government - subject [gerund phrase] is - verb the key to stability - subject complement [noun phrase] Some more information here: https://parentingpatch.com/grammatical-forms-english-noun-clauses/ [excerpt] Conjunctions are “words that link words, phrases, and clauses.” A subordinating conjunction is a conjunction that introduces a subordinate or dependent clause. Subordinating conjunctions that introduce noun clauses are also referred to as noun clause markers. The subordinating conjunctions in English that introduce noun clauses are that (which can be omitted in certain cases), if, whether, wh- words, wh-ever words, and sometimes for.