I believe that the adverb phrase in this sentence is "during the fifteenth century". We know that adverb phrases are a group of words which are used to modify a verb, adverb or adjective. Here, I think that the adverb phrase is modifying the verb 'lived.
I think it's most likely that the flood deposited silt on the land, which made it fertile and allowed crops to grow in it.
Assuming the word "cheerleaders" is underlined, your answer is B. Plural. This is because there is more than one cheerleader.
I hoped this helped! Please rate, thank, and pick the Brainliest answer (not necessarily mine!). Thanks, it really helps! :)