Final answer:
The word 'mimic' is the correct choice for the sentence, meaning to imitate someone's actions or words.
Step-by-step explanation:
The correct word for the sentence If you mimic someone, you do the same things that he does is a) mimic. The word 'mimic' means to imitate or copy someone's actions or words, often with the intent to entertain or ridicule. Other options such as 'dominate' or 'collaborate' do not fit the context of doing the same things that someone does. 'Dominate' means to have power and influence over, 'collaborate' means to work jointly on an activity or project, and 'ignite' is to set on fire or spark an emotion or situation.