Which of the Following Statements About the Relationship Between Sex

Which of the following statements about the relationship between sex and gender is incorrect?

A) Sex is the same as gender.
B) Sex refers to physical differences between males and females,whereas gender refers to the cultural meanings assigned to sex.
C) Sexual differences are biological;gender differences depend on cultural definition.
D) Gender differences began with human culture,about 2.5 million years ago.
E) The biological differences between males and females have decreased since 2.5 million years ago.