Why Are Cilia Described as an Example of Unity Underlying

Why are cilia described as an example of unity underlying the diversity of life?

A) Cilia are cells that function in locomotion.
B) Humans and Paramecium both share the same architecture of their cilia.
C) Cilia have an elaborate system of tubules.
D) Cilia provide motility to all the cells on which they reside.
E) Imprints of cilia have been found in the fossilized remains of prokaryotes.