Final answer:
The epiphysis lines are visible until bones are completely fused at a certain age.
Step-by-step explanation:
The statement is True. The epiphysis lines are visible until bones are completely fused at a certain age. The epiphysis lines are the remnants of the epiphyseal plates in mature bones.
During endochondral ossification, a primary ossification center develops within the epiphysis, not the diaphysis or any other part of the bone. The epiphyseal plate is responsible for bone lengthening through the growth of cartilage cells. However, the epiphyseal plates do disappear before birth as the bones fully develop and fuse.
Long bones stop growing and the epiphyseal plates close around the age of 18 in females and 21 in males, resulting in the formation of the epiphyseal line or remnant. This process involves the replacement of cartilage with bone.