Final answer:
The suture marks in the skull gradually change over time as a person ages. In newborns and infants, the fontanelles allow for skull growth and flexibility. However, as the bones enlarge, the fontanelles narrow and convert into sutures, which gradually ossify and fuse the adjacent bones.
Step-by-step explanation:
As a person ages, the suture marks in the skull gradually change. In newborns and infants, the suture marks are wider and filled with fontanelles, which are areas of connective tissue between the bones. These fontanelles allow for skull growth and flexibility. However, as the skull bones enlarge, the fontanelles narrow and convert into sutures, which are narrow layers of connective tissue between the bones. Over time, the connective tissue in the sutures ossifies and fuses the adjacent bones, causing the suture lines to gradually disappear.