Rewrite the sentence replacing the nouns or noun phrases with pronouns. The dog wagged the dog's tail when the dog saw the dog's owners walking toward the dog.

The dog wagged its tail when it saw its owner walking toward it.

Explanation:

parts of an essay — traditionally, it has been taught that a formal essay consists of three parts: the introductory paragraph or introduction, the body paragraphs, and the concluding paragraph. an essay does not need to be this simple, but it is a good starting point.