He shoots a basketball with either hand. which best identifies the adverb phrase and the word it modifies?

In this example, the adverb phrase is "with either hand." The adverb phrase provides more details about how the action of the verb was performed. It can provide information regarding how, why, where, when and in what way the action happened. In this sentence, the word the adverb phrase modifies (in other words, the verb of the sentence) is "shoots."

- "the answers are a and b.  

when cullen speaks of planting while others reap, and standing "abject and mute," he is speaking about the racial injustices present in american society. as these injustices have changed over time, the american identity  has also shifted. those changes are, in turn, reflected in american literature."