Question

why does the pelvic area in the girls broaden at pubrty?

Answer 1

the pelvic area in the girls broadens at puberty, as at the age of puberty girls are matured to bear baby, so for the accommodation of the baby pelvic area broadens.

Answer 2

It is due to changes which occur at puberty. Or
it is due to hormones secreted by ovary called estrogen which is responsible for widening.It occurs for the accommodation of child in the uterus. The fat gets deposited in this region also.