This is an excellent starter assignment for getting to the Common Core descriptive writing strand with your students.
A paragraph contains a group of closely related sentences, all dealing with a particular topic or idea. One sentence usually states the main idea of the paragraph. The others detail and describe whatever the author wants to say about it.
I use this exercise early in the semester with students to introduce the basics of descriptive writing before getting into the details later in the semester. The first part of the work is done quietly at the beginning of class while I do attendance. Once this is done, students orally go over their answers and then we begin on the "you do it" section where the student composes their own writing up to the expectations and standards that are listed and taught.