Thesis Statement Again

There are few inventions that have had such a large and important impact in the world as the traffic light. Almost every person uses traffic lights every day. And while it may be frustrating at times to be stopped by many red lights in a row, they serve an important purpose. Without them, streets and highways would be a crazy nightmare. Traffic lights greatly improved automobile travel by managing traffic effectively, creating a safer driving environment and reducing travel times.

What color is the sentence that is the thesis statement?

What word and punctuation mark would I most likely find in a strong thesis statement?

4. Which of the following makes the best thesis statement?