Bones are strengthened by having muscles pull on them.
(Bones; are strengthened; by having muscles pull on them) (Bones; by having; muscles pull on them) Context(Bones by having,List([0, 32))):(muscles; pull; on them)
Bones by having,List([0, 32))
Bones Bones muscles
are strengthened by having pull
by having muscles pull on them
muscles pull on them
on them