Answer: A Microtubules
Explanation: The cytoskeleton is composed of at last three different types of fibers: microtubules, microfilaments, and intermediate filaments. These fibers are distinguished by their size with microtubules being the thickest and microfilaments being the thinnest.
Pull Of Gravity , that is why you have weight or else without gravitational pull you only have mass hence the equation w = mg
B. Clay particles are the smallest