The main point introduces causes, effects, or both. Here is an example of a topic sentence for a paragraph:

Remember that the main point for an essay can be a little broader than one for a paragraph (see “Paragraphs vs. Essays in Cause and Effect”).

Whereas the topic sentence focuses on just one major benefit of regular exercise, the thesis statement considers multiple benefits.

NOTE: When you are writing about causes and effects, make sure that you do not confuse something that happened before an event with a real cause or something that happened after an event with a real effect. For example, if you have pizza on Monday and get the flu on Tuesday, eating the pizza is not the cause of the flu just because it happened before you got the flu, nor is the flu the effect of eating pizza. You just happened to get the flu the next day.