Women's voices are generally higher than men's voices because their vocal cords tend to be ________ and to vibrate ________.

The correct answer details that women's vocal cords tend to be shorter, which contributes to producing a higher pitch. Shorter vocal cords vibrate at a higher frequency compared to longer vocal cords, which typically produce a lower pitch. This phenomenon relates to how the structure of the vocal cords affects sound generation. The tension and length of the vocal cords determine how quickly they vibrate; thus, shorter cords vibrate faster and create a higher sound frequency, resulting in a higher-pitched voice commonly associated with women. Understanding the correlation between vocal cord length and pitch is key to grasping this aspect of human biology and perception of voice characteristics.