Complex sentence: Some stillborn skeletons show almost no mineralization; others have marked bony undermineralization and severe rachitic changes; and occasionally, there can be peculiar complete or partial absence of ossification in one or more vertebrae.
Split into simpler sentences: Some stillborn skeletons show almost no mineralization; others have marked undermineralization and severe rachitic changes. Occasionally there can be peculiar complete or partial absence of ossification in one or more vertebrae.