Final answer:
The sentence 'The pillar that sustains the roof is crumbling' is a complex sentence.
Explanation:
The sentence 'The pillar that sustains the roof is crumbling' is a complex sentence. In a complex sentence, there is an independent clause (main clause) and at least one dependent clause. In this case, 'The pillar is crumbling' is the independent clause, and 'that sustains the roof' is the dependent clause.
Learn more about Sentence Structures here:
https://brainly.com/question/40225273
