Human facial expressions differ from those of animals in the degree ______ they can be controlled on purpose.

A. with which           B. to which        C. of which      D. for which

Human facial expressions differ from those of animals in the degree ___ ___ they can be controlled on purpose.

A. with which        B. to which

C. of which    D. for which

Human facial expressions differ from those of animals in the degree __________ they can be controlled on purpose.

A. with which B. to which

C. of which    D. for which

Human facial expressions differ from those of animals in the degree ___ they can be controlled on purpose.

A.with which                                            B.to which

C.of which                                               D.for which

Human facial expressions differ from those of animals in the degree ______ they can be controlled on purpose.