Questions: Include a subject heading on each research note. Put all the information from each source on a single note. Use a different format for notes from internet sources and library documents. All of these answers are correct. Both include a subject heading on each research note and use a different format for notes from internet sources and library documents.

The answer is the fourth one: All of these answers are correct.

Explanation for each option:

1. Include a subject heading on each research note: This is a good practice as it helps in organizing and categorizing the notes, making it easier to reference them later.
2. Put all the information from each source on a single note: This ensures that all relevant information from a particular source is kept together, which can help in maintaining the context and avoiding confusion.
3. Use a different format for notes from internet sources and library documents: Differentiating the format based on the source type can help in quickly identifying the origin of the information, which is useful for citation and verification purposes.
4. All of these answers are correct: Since each of the individual practices mentioned above is correct and beneficial for effective note-taking, this option is the most comprehensive and accurate.

Summary: The correct answer is the fourth one: All of these answers are correct. Each practice mentioned contributes to better organization and clarity in research notes.