Each body paragraph includes a topic sentence that tells readers what the paragraph is about; supporting sentences that discuss the idea or ideas in the topic sentence, using examples and/or evidence to support that discussion; and a concluding sentence that emphasizes the importance of the supporting sentences... Each body paragraph should have three main sentences: a topic sentence, which expresses the main idea of the paragraph; one or more supporting sentences, which add detail or clarification about this main idea; and a concluding sentence that summarizes the information in the paragraph. For example, here is a body paragraph for a student who wants to explain how birds are able to fly with such ease despite having very little muscle control over their wings: Birds are able to fly because they use their feathers to generate lift, just like an airplane. However, while airplanes need rigid structures to function (such as the fuselage of a plane), birds can fly with much more flexible bodies because they have thick layers of fat and muscles near their wings that allow them to bend without breaking. Supporting sentences would include details about how birds achieve lift with their feathers, including describing how different parts of a bird's wing work together to create drag when it moves through the air.