Final answer:
The subject of this question is English, and the best word choice to complete the sentences would be 'revolving'.
Step-by-step explanation:
The subject of this question is English, as it is asking the student to choose the best word to complete each sentence using context clues and potentially a dictionary.
Knowing the meaning of the root word can help with understanding related words. In this case, the root word is 'volv-', which means to turn. Based on this, we can eliminate options b (revolt) and e (devolved) since they do not have the meaning of 'turning around' like the root word suggests.
Options a (evolve), c (revolving), and d (volutioon) are related to the concept of turning around, but the best word choice to complete the sentences would be c (revolving) as it fits the context of objects or things that are turning around.