A femur is a leg bone found in a human skeleton. When evaluating the human body's levels of organization, a femur is best classi
fied as — A.
an organ, because it is part of the skeletal system.
B.
an organ system, because it is composed of many cells.
C.
an organelle, because it is composed of many tissues.
D.
an organism, because it is part of the skeletal system.
