Answer:
c.
Step-by-step explanation:
1) Microtubules are components of a various array of structures. They form the mitotic spindly of dividing cells and core of flagella.
2) Microtubules are strong enough to resist or oppose the forces that can bend or compress fiber. Microtubules provide mechanical support like the poles support the structure of a tent.
3)The placement of cytoplasmic microtubules in a cell, determines the shape of that cell.
4) Microtubule are highly sensitive to various environmental effects.
For e.g. Very low levels of free calcium can destabilize microtubule.
This was the reason that researchers could not study microtubules in vitro.
Also Cold temperatures lead to rapid depolymerization of microtubules.