Final answer:
A sentence that introduces a paragraph subject to a reader is called a topic sentence. It states the main idea or point of the paragraph and helps the reader understand the paragraph's focus.
Step-by-step explanation:
A sentence that introduces a paragraph subject to a reader is called a topic sentence. A topic sentence is usually found at the beginning of a paragraph and it states the main idea or point of the paragraph. It provides a clear focus and helps the reader understand what the paragraph will be about.
Learn more about Topic sentence