Please help me correct these sentences (I'm studying for a grammar test)?

Question

So I'm studying the grammar portion of the Teas test. I found this great grammar workbook I bought in high school that I never used. The only problem is that there is no answer key so I'm not sure if I'm doing all of it right. So if you can help me w/ some of these sentences, I'd be thankful

Add commas where necessary and explain why (I added some with my explanations, but I'm not sure if they are correct):
1) Many of the first settlements in California were founded by Father Serra, who liked to take long walks between them. (comma after Serra b/c it's a nonrestrictive clause?)

2) The word's origin is oikos, the Greek word meaning "house." (Don't know why comma goes there. Appositive phrase?)

3)Ecology is the study of an enormouse "house," the world of all living things (comma there because it's an appositive phrase?)

4)Perhaps Gladys you have read the story "My Delicate heart Condition."

5) I know Ms. Reaves that you read Bambara's book The Black Woman.

Answer 1

1 to 3 correct
4. the story, My........
5. book, The..........