1) They both baked their favorite cake.
Because genetics is now progressing so rapidly.
The subordinate clause starts with a subordinating conjunction and contains the entire dependent clause. Because is a subordinate conjunction and makes the clause dependent because you need to know what's next. Hopefully answer choice D has all the right pieces. The main clause is "it is revolutionizing medical research". This clause is a complete idea by itself and is not a subordinate clause.
I think the best choice is the last one: <span>d. appropriate length.
. Length is also determined by the purpose of the work and the context in which it will appear. (for examples, some newspaper articles have per-specified length). </span>
I think it means that you should put in another idea
