Evaluating Structural Formulas I

Two isomeric structural formulas (I & II) are drawn below. Questions concerning these structures shoud be answered by entering a number or selecting the desired response as designated.
Jmol models of these structures may be examined by Clicking Here

1. How many stereogenic centers are present in Structure I? How many stereogenic centers are present in Structure II?
2. Which of the following statements best describes the relationship of Structures I and II? They are diastereomers. They are different conformations of enantiomers. They are different conformations of the same compound. They are identical conformations of the same compound.