Why do writers use appositives and appositive phrases in their writing?

Which of these authors wrote a story that revolved around a captains underwater adventures with his crew and a sub marine long before the submarine was actually invented

Read this sentence from the story of my life by helen keller. the most important day i remember in all my life is the one on which my teacher, anne mansfield sullivan, came to me. which element of plot does this sentence best represent?

Me read the letter. dear aunt mary, you for the wonderful painting. you are so talented! i was thrilled that you chose to paint horses. you must have remembered that i was crazy about horses when i was a little kid—and i still love them. i have hung the painting in my room so that i can see it every morning when i wake up. your loving niece, celia what makes this letter appropriate for its intended audience? it is written from the third-person point of view. it is concise and impersonal. its sentence structure is varied. its language is informal.