The present participle is "winning." It is used as an adjective to describe the "team."
Explanation:
A "present participle" is being used in order to express an action that is present. This uses the<em> -ing form of the verb</em> in order to show that an action is happening at the moment. It can be used as an <em>adjective</em>. For example:
A<em> crying</em> boy.
The <em>bouncing</em> ball.
So, in the example sentence above (The winning team received a trophy after the game), the present participle is "winning." This modifies the word "team."
Remember that compared to past participles, a present participle is often active while a past participle is often passive.
A. Somewhat. The sentence still makes sense without it, and it doesn't matter how skeptical she is since she's still doing research either way, so it can be cut out.