Step-by-step explanation:
The question you want me to answer is undefined so I will explain from both sides.
Firstly, "necesitas" is wrong. Necesitas is the "tú" conjuagate form of necesitar. It would be used in cases such as:
¿Tú necesitas un vaso de agua?
The yo form for necesitar would be necesito. Now that we have the correct verb, lets look at the sentence from two sides.
Depending on your question, the sentence can be written in one of two ways.
1. Yo no necesito un papel en la clase de educación física.
2. Yo necesito un papel en la clase de educación física.
In sentence 2, you don't need anything in between the "yo" and "necesito".
Again, this is subjective as I don't really know the question they are asking you. Though I hope I helped you!