What punctuation mark separates complete thoughts in a sentence?

The semi-colon serves as an effective punctuation mark to separate related complete thoughts within a sentence. It allows writers to connect two independent clauses that are closely related in content without the need for a conjunction. Using a semi-colon helps to create a smoother flow between ideas, showing a relationship and enhancing clarity.

For example, in the sentence "I enjoy studying power engineering; it is a complex but rewarding field," the semi-colon connects two complete thoughts that are inherently tied together. This illustrates how the use of a semi-colon can improve the cohesiveness of writing, allowing the reader to understand the relationship between the two ideas more clearly.

In contrast, other punctuation marks, like the ones offered in the choices, serve different functions. A hyphen is primarily used to join words or parts of words to form compound terms. A colon is typically used to introduce lists or explanations rather than link independent clauses. A period, while it does separate complete thoughts, is used to end a sentence instead of linking thoughts together. This distinction underscores the specific role of the semi-colon in connecting related ideas within a sentence.