Anoun that completes an action is called a/an
a. predicate.
b. complement.
c. object.
d. subject.

The answer is D) Subject.
a predicate is the part of the sentence where the verb (the action) enlies. The subject is the part of the sentence that contains the noun (the person, place, thing, or idea that is doing the object)

Ifound the exercise on the internet. attached is the list mentioned above.in order for a compound to be considered optically active it can't have any axis or plan of symmetry. the molecule  shouldn't also  be superimposable on its mirror image.with such considerations, the compounds that are optically active are: -third compound on the first image is optically active; -second and third compound from the second image are optically actives.