Question

Pelvic region of girls wider at puberty

Answer 1

Due to the increase of pelvic bone.

Answer 2

When women get into puberty, the ovaries start producing an hormone known as estrogen. Estrogen is responsible for the widening of the female pelvis. The bones of the pelvis are widen by this hormone as a means of preparing the woman for the process of childbirth. The estrogen are also responsible for the deposition of fat on the hip region of women, making them have a smaller waist and more pronounce hip region.

                                   

or

to secretion of estrogen harmone which is responsible for preparation of girls to their child birth.this region is also a place whr the fat is stored in female.these secretions are high during puberty and thus pelvic area of girls become wider during puberty