Answer and Explanation:
Dicondylic Skull : It has two occipital condyles, with the help of these two condyles skull is connected by first vertebra of vertebral column
i.e, Atlas, this type of skull is called dicondylic skull.
Monocondylic skull : Only one occipital condyle is present in skull, this type of skull is called monocondyl skull.
Ribs are present in neck and thorax ribs of thoracic region make true sternum