Hi there!
We know that explanatory writing is basically informational, or it gives information accurately. For example: When defining explanatory writing, it's basically giving you the evidence or information that's being gathered from an essay, story, or a poem. Like gathering the theme, plot, or/and main idea.
When you analyze and select examples from texts as relevant to the cultural theme of your essay, your basically taking the evidence and the information from the texts that your looking and summarizing at. Your also explaining what the evidence and information you've gathered.
I hope this helps and have a fantastic day!