I believe the correct answer is sentences 2,5 and 6.
Complex sentences are composed of one independent
clause and at least one dependent clause. The examples from "The Enigma
Machine” which are complex sentences are:
<span>2. </span>For
example, Bletchley Park was crucial in the Battle of the Atlantic, which lasted
six years.
5. This
was provided in a codebook, which was a monthly list of daily keys distributed
to various networks in the German military.
6. Since
the Enigma machine could encrypt text into over 150 trillion possible
combinations, Germans were convinced the codes were not decipherable.
Broad, as there is a wide range of things to explore in the subject, so it is a large/ broad subject. Science for example has biology, chemistry, and physics under it, and many things under each of these subtopics, which is why, science is a broad topic/subject, whereas if you were to narrow it down to the atoms (Chemistry) it would be less broad. and more limited, any subject can be impressive, no matter how limited nor broad it is.
