Teratomas are unusual forms of cancer because they
are composed of tissues such as tooth and bone not
normally found in the organ in which the tumor
appears.
(A) because they are composed of tissues such as
tooth and bone
(B) because they are composed of tissues like tooth
and bone that are
(C) because they are composed of tissues, like tooth
and bone, tissues
(D) in that their composition, tissues such as tooth
and bone, is
(E) in that they are composed of tissues such tooth
and bone, tissues