Final answer:
The sentence 'Although she left her house early, Addison barely made it to the train station in time' is a complex sentence. It includes one main clause and one subordinate clause introduced by 'although'. The other sentence provided is a compound sentence because it consists of two main clauses joined by 'and'.
Step-by-step explanation:
The sentence in question, 'Although she left her house early, Addison barely made it to the train station in time,' is a complex sentence. This is because it contains one main clause (Addison barely made it to the train station in time) and one subordinate clause (Although she left her house early). The main clause can stand alone as a sentence, while the subordinate clause cannot and provides additional information to the main clause. A complex sentence typically contains a subordinating conjunction, such as 'although', which is present in this sentence.
Conversely, 'Her dog happily fetched his tennis ball from the muddy puddle and eagerly waited for her to throw it again' is a compound sentence. It is composed of two main clauses ('Her dog happily fetched his tennis ball from the muddy puddle' and 'eagerly waited for her to throw it again') joined by the coordinating conjunction 'and'. Both clauses can stand alone, making it a compound sentence.
A compound-complex sentence combines elements of both, having at least two main clauses and one or more subordinate clauses. These sentences allow you to express multiple ideas in one sentence.