No necessaryily. Line spacing is the space between lines within a paragaph. Paragraph spacing is the space between paragraphs on a page.
An expression or phrase that immediately precedes the signature in a letter or email such as: Sincerely yours.
On Home tab in Paragraph section, look for two arrows symbol (next to alignment options).
1.5 I think.
Line spacing is the space between the lines of your document. If you need some space for your teacher to correct your paper, then you can apply double spacing. See related link for reference.