What object in the solar system has a composition similar to that of the gas giants?
Well, it is definitely NOT the Sun. The closest other is a comet. I am not certain what your teacher had in mind here.
Describe how a rock can fore by evaporation. What type of rock is it?
First, if you have a question, it is much better to put it in as a separate post in <Post a New Question> rather than attaching it to a previous question, where is more likely to be overlooked.
Since this is not my area of expertise, I searched Google under the key words "rock from evaporation" to get these possible sources:
http://journals.cambridge.org/action/displayAbstract;jsessionid=0FF6EBA3656D68CE740646A3ECD66F7A.tomcat1?fromPage=online&aid=325454
http://adsabs.harvard.edu/abs/2005JFM...537...35T
I hope this helps. Thanks for asking.