What element does a thesis statement typically include?

A thesis statement serves as a roadmap for an essay, clearly articulating the main argument or claim that the writer intends to explore and support throughout the text. This central idea is essential because it gives readers insight into the essay's purpose and direction. By including the main argument, the thesis allows for a focused approach, guiding both the writer's development of ideas and the reader’s understanding of what to expect in the body of the essay.

The other options do not accurately capture the primary role of a thesis statement. A call to action, while important in persuasive writing, typically appears in the conclusion or final sections of an essay rather than in the thesis itself. A summary of evidence is a component that might come later in the essay as the writer supports their claim, but it's not part of the thesis statement. Lastly, a list of sources is relevant for citation and credibility, but it does not belong in the thesis statement, which is focused solely on presenting the main argument.