A 3-year-old boy is

brought to the pediatrician. The parents are worried that the boy has started

falling unexpectedly when walking. Physical examination reveals muscle weakness

especially in the lower extremities. As muscular dystrophy is suspected here

based on history and other investigations, a biopsy of his skeletal muscle is

taken and sent to a pathologist. However, the pathologist's report states that

the sample contains only healthy muscle tissue. Which of the following

characteristics can be used to describe the specimen?