I don't know if i am the right candidate to put up an explanation for your query but i will try my bit
FANBOYS- The conjunctions used to join two independent clauses or you can also join the two independent clauses using a semicolon.
E.g. The teacher scolded Ram, because he came late.
Because he came late is the dependent clause here.
The dependent clause became dependent because of the presence of 'because' here which is a subordinate. In absence of because there would have been two independent clauses.
Teacher scolded Ram.
He came late.
In short the dependent clause is due to the presence of 'because' which is a subordinator in the sentence.
E.g. 2 Although the economy is strong, the retail industry is struggling.
Again here although is working as a subordinator making the first clause as dependent clause.
We could have used 'But' in the sentence as well and the sentence would have been fine.
The economy is strong but the retail industry is struggling.
Therefore, Moreover and other related words are not the subordintors and thus cannot be used for joining two clauses. That's the reason we see semicolons in these sentences.
Hope it makes sense.
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