Answer:
1. whether (if); because (since)
2. "... the economy had changed, the population had shifted and the war had ended"
Explanation:
In formal, informative or busines communication it is important to be clear and concise with as few words as possible.
In this sentence we see that "as to whether" and "due to the fact that" are highlighted, suggesting that these phrases should be revised.
Debating on something already means that you are choosing in favor or against certain topic. That meaning is already found in the word it self, so it is unnecessary to write "as to whether" after it. Only "whether" would be quite sufficient. In some instances this entire phrase could be replaced by simple "if".
Also, the phrase "due to the fact that" should be replaced with its synonim. Connector "because" (or even since) has the same meaning as the highlighted phrase.
When listing actions one should always pay attention to maintain a parallel structure in sentence. That basically means that all listed clauses should contain same grammar structure. In simple terms, it means that verbs should be in the same tense and the sentences should follow the same pattern. Listed actions here are:
- the economy had changed
- there were shifts in population
- the war had ended
Note how first and third sentence have that simple subject-verb pattern. If we want to maintain parallel structure, we should rewrite the second sentence to correspond to that pattern. This can be done by making the object of the sentence (population) a new subject and forming a verb from the subject noun (shift (n.) ---> shift (v.)). Since the original sentence was in past simple tense, the new one should also be:
"the population shifted"
Now, our listed verbs are: had changed (past perfect tense), shifted (past simple tense) and had ended (past perfect tense).
Now, the goal is to put them in the same tense. Since all these actions happened and ended in the past, we should use past perfect tense. That means that only verb "shifted" needs revision to "had shifted".
Finally, the second half of the sentence should write "... the economy had changed, the population had shifted and the war had ended".
