Which two are the benefits of using a quaternion? (Choose two.)

A.
To transform a mesh to a new orientation

B.
To connect armatures to mesh vertices

C.
To find the normal of a plane

D.
To implement transparency

E.
To perform rotation calculations

Explanation:
http://blogs.msdn.com/b/rezanour/archive/2012/04/29/math-primer-series-rotationrepresentations-and-quaternions.aspx