Final answer:
The independent clause among the options provided is "The boats depart quickly" as it contains a subject and a verb and can stand alone as a complete sentence. The other options are dependent clauses because they begin with subordinating conjunctions or relative pronouns and cannot stand alone to express a complete thought. The correct answer is option: The boats depart quickly.
Step-by-step explanation:
An independent clause is a group of words that contains a subject and verb and can stand alone as a complete sentence because it expresses a complete thought. In the question provided, the option "The boats depart quickly" is an independent clause. The subjects and verbs of the clauses presented are as follows: 'the lake' and 'appears' in the first clause, 'the boats' and 'depart' in the second, 'the ducks' and 'swim' in the third, and 'there' and 'are' in the fourth. The key characteristic that distinguishes the independent clause here is that it doesn't begin with a subordinating conjunction or relative pronoun, and it formulates a complete thought that doesn't rely on additional information.
In contrast, the clauses "Even though the lake appears full," "While the ducks swim away," and "Whether there are any fish" are all dependent clauses because they cannot stand alone as complete sentences. They start with subordinating conjunctions or relative pronouns, indicating that they require additional information to form a complete idea. This makes them unable to convey a complete thought on their own."