Answer:
1.) A sentence that expresses the main idea of the paragraph in which it occurs
2.) Every paragraph should include a topic sentence that identifies the main idea of the paragraph. A topic sentence also states the point the writer wishes to make about that subject. Generally, the topic sentence appears at the beginning of the paragraph.
3.) The topic sentence contains two parts: the topic and a controlling idea. The topic is WHAT the paragraph is going to be about, and the controlling idea explains WHY the paragraph is being written. The topic sentence helps your reader understand the purpose of your paragraph.
4.) I am not sure
Explanation:
