Answer :
The feature that you need to use in examining and make a determination whether the skeletal remains in the pelvis is either male or female is by analyzing its size and construction. It is because males have larger pelvis bone and are robust elements compared to females who have smaller and are light in terms of construction.
Answer: the size
Explanation: Even the fact that there are at least seven diagnostic criteria to differenciate female and male pelvis, one of the most important is the size of the bone. A female pelvis is larger and broader than a male pelvis. The male pelvis is taller, narrower and it is also more compact than the female pelvis. This is why, if I had to help in a police investigation, I would check the size of the bone.