Malia Was Recently Awarded 1 Million Dollars from the National

Malia was recently awarded 1 million dollars from the National Institutes of Health to study pain at the molecular level.One stipulation of the grant is that she include equal numbers of women and men participants in her sample to test for variance among women and men.This is an example of the ____________ approach to research.

A) evolutionary
B) gender neutral
C) differences
D) similarities