Answer:
A non-fiction book that examines World War II. All are examples of informative texts. Informative text can appear in newspapers, textbooks, reference materials, and research papers. Informative text is always nonfiction.
Explanation:
The second alarm circuit hadn't been connected up at the time.
The subordinate clause here is A, "as the layers of ash slowly compressed". Subordinate means that it cannot exist on its own, it has to be a part of the main, independent clause.
