Use the Following to Answer the Following Questions -Centrioles, Cilia, Flagella, and Basal Bodies Have Remarkably Similar Structural

Multiple Choice

Use the following to answer the following questions. All three are involved in maintenance of cell shape.
$\begin{array}{c}\begin{array}{|l}\hline\\ \text {Property}\\\hline\\\\ \text {Structure}\\\hline\\ \text {Diameter}\\\hline \text {Main}\\\text {functions}\\\hline \end{array}\begin{array}{|l|}\hline \text { Microtubules (tubulin}\\\text { polymers) }\\\hline \text {Hollow tubes; wall}\\ \text {consists of 13 columns}\\ \text {of tubulin molecules}\\\hline \text {\( 25 \mathrm{~nm} \) with 15-nm}\\ \text {lumen}\\\hline\\ \text {Cell motility}\\\hline \end{array}\begin{array}{l|}\hline \text { Microfilaments (actin}\\ \text { filaments) }\\\hline \text { Two intertwined strands}\\ \text { of actin, each a polymer }\\ \text { of actin subunits}\\\hline\\ \text { \( 7 \mathrm{~nm} \) }\\\hline\\ \text { Cell motility}\\\hline \end{array}\begin{array}{l|}\hline \text {Intermediate}\\ \text {filaments}\\\hline \text {Fibrous proteins }\\ \text {supercoiled into}\\ \text { thicker cables}\\\hline\\ \text {8-12nm}\\\hline\\ \text {Anchorage}\\\hline\end{array}\end{array}$

-Centrioles, cilia, flagella, and basal bodies have remarkably similar structural elements and arrangements. This leads us to which of the following as a probable hypothesis?

A) Disruption of one of these types of structure should necessarily disrupt each of the others as well.
B) Loss of basal bodies should lead to loss of all cilia, flagella, and centrioles.
C) Motor proteins such as dynein must have evolved before any of these four kinds of structure.
D) Evolution of motility, of cells or of parts of cells, must have occurred only once.
E) Natural selection for motility must select for microtubular arrays in circular patterns.