Compound. The simple sentence would be 'they were very busy'
The themes that apply to all the selections in this unit is A and D
Answer:
I think that Wolff means a concealed or closed up tape records.
Explanation:
The topic sentence for the paragraph above is A. Sentence 1. A topic sentence is supposed to give the general idea of a paragraph. Sentence 1 briefly describes what and where plates are in the Earth's crust. The rest of the sentences give more detail about tectonic plates.
