Describe an important idea from the text that this visual helps you understand.

Images create a visual representation of the text, while the caption is the text that accompanies an image, giving it meaning or clarification.

Explanation:

Much more than merely embellishing or elucidating the text, illustration can thus represent, describe, narrate, symbolize, express, play, persuade, normalize, punctuate, in addition to emphasizing its own configuration, draw attention to its support or to the visual language. It is important to note that the image rarely performs a single function, but, as with verbal language, functions are organized hierarchically in relation to a dominant function.

On the other hand, subtitles are the texts that appear immediately below or alongside (or, more rarely, above) an image, identifying it, contextualizing it and adding some information from the text that accompanies it.

Sample response: The diagram shows that Kingsley traveled upriver using several different boats. This method of travel helped her get to where the Fang tribe lived, where she traded goods.

Explanation:

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)

its repetition emphasizing that the chain is his own. sorry if i am wrong.