Read these sentences from Section 3 of "Cool Eye Tricks." It should look like there’s a hole in your free hand. The objects in the distance should be visible through this hole. How does this part of Section 3 contribute to the development of ideas in the text? It explains why this trick is so impressive to perform. It tells the reader how this trick is accomplished. It tells the reader the expected outcome of the trick. It explains why this trick is so important to learn.

C. It tells the reader the expected outcome of the trick.

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taking into account that a theme is the central topic a text treats and can be developed through a story, play, poem etc. the following are themes that can be further developed:  

my best friend jeffrey has many unusual interests. (the story could be about each of the unususal interests)

once a man gives his soul over to evil, he can never go back. (this could be a saying or a proverb)

the three sheepdogs lay around the yard all day. (it could be developed detailing how each of these sheepdogs lay around)

a priest's collar has an unusual effect upon people. (it could be developed detailing the different effect upon people)

innocence is a powerful force in a world full of corruption. (it could be developed detailing how is a world full of corruption)

king lear is a play shakespeare wrote later. (it is just a sentence and doesnt give any idea or topic to be discussed in details.

evil often wears the disguise of innocence. (this could be a saying or a proverb)