Answer:
Hello there!
I can't write this for you, but I can help you out a little. When you "explain how each example represents the time period it is from", you could find examples within the option you chose that relate to the time period. Perhaps the selection is on an event in history, so you could talk about the significance of that event. Or, it mentions something that would be prevalent in that time (such as a horse-drawn carriage).
Then, you need to explain how they are different from each other. A poem, short story, and historical document are obviously going to have different writing styles. A poem/short story may be based off of a fictional event or it may exaggerate a real event, whereas a document will be factual. Those are some more obvious differences you could point out. You could also say if each selection creates a negative or positive outlook on the time period. I hope this helps!