Read the following excerpt from a student essay. How can the writer best improve his or her grammar and mechanics?
Everyone agree that recess is important for children in elementary school, but what about middle school students? I believe that students in middle school needs time to relax and have fun during the school day. A period of free time in the afternoons give students the opportunity to go outside and enjoy some fresh air. Studies shows that exercise benefits students' attention spans. Exercise can also reduce stress, which many middle school students face on a daily basis. Therefore, middle school students in our country deserves recess, too.

 - by fixing subject-verb agreement errors
 - by adding missing commas
The writer could best improve his or her grammar and mechanics by fixing subject-verb agreement errors.
For example, the writer could change the first underlined verb to agree with the indefinite pronoun everyone and the others to agree with their simple subjects.
Everyone agree that recess is important for children in elementary school, but what about middle school students? I believe that students in middle school needs time to relax and have fun during the school day. A period of free time in the afternoons give students the opportunity to go outside and enjoy some fresh air. Studies shows that exercise benefits students' attention spans. Exercise can also reduce stress, which many middle school students face on a daily basis. Therefore, middle school students in our country deserves recess, too.