Typically, if the words are your own you do not need to enclose them in quotation marks. However, if you specifically mean the words to be understood as dialogue, you should put quotation marks around them.
I need to add quotation marks in that sentence
Use single quotation marks to indicate a quote within a quote.If you're using a quote that contains a quote you'll need to surround the embedded quote with single quotation marks.
Yes. Anytime you are using someone else's words in your own writing, you must use quotation marks to indicate so.
No, it is not necessary to put the definition of plagiarism in quotation marks unless you are directly quoting a source. Otherwise, you can simply state the definition in your own words or paraphrase it.
introduce and provide context for each quotation
If you're using a quote that contains a quote you'll need to surround the embedded quote with single quotation marks.
Quotation marks should be used if the passage says "Bob thought" or something similar. In this case, the quotation marks are used in the same way they would be used if the passage said "Bob said"
something that is necessary for survival - took the test
Quotation marks are not necessary when indicating a character's thoughts in a story. It is common to use italics to show a character's inner dialogue or thoughts without the need for quotation marks.
Exact quoting of an author should always be enclosed in quotation marks and cited. If you paraphrase, it does not need quotes. Fair use word count is something different than when to use quote marks.
No
Well, it doesn't need quotation marks but it does have to be capitalized and it has to be in italics. If it's a name of the article in a magazine, then you have to underline it too. That's what I think.