Which arrow(s) indicates chiral center(s) in the compound shown?

Which statement is correct concerning the relative stabilities of the two conformations, A and B, below?  

Identify the lowest energy conformation of butane as a Newman projection looking down the C2-C3 bond.

What is the appropriate IUPAC name for compound shown?

What is the correct order of the Cahn-Ingold-Prelog ranking of the following substituents as used in assigning R and S configurations of chiral centers? (higher ranking > lower ranking) ​ 1. −CH2OH 2. −CHO 3. −OCH3 4. −OCOCH3 ​

Bonus question Which are identical compounds?

Which of the following illustrates a correctly positioned equatorial OH?

What is the % ee of a sample of carvone that exhibits a specific rotation of −40, given that the specific rotation of (R)-carvone is −61?

Is the alkene on the left in the molecule below E, Z, or neither?

Which of the following Newman projections represents the most stable conformation of 2-methylbutane?