The cytoskeleton plays a huge role in the function of an organism and cell. The main function of cytoskeletons is to help maintain the structure of the cell. An important characteristic of cytoskeleton structures is dynamic instability, which allows these structures to polymerize and depolymerize. Some common cytoskeleton structures in the cell include microtubules and actin. Dynamic instability allows these structures to move and help the cell carry out processes like chromosome segregation (microtubules) and muscle contraction (actin). In chromosome segregation, microtubules must be able to become shorter to pull chromosomes apart. It would be difficult for the cell to carry out vital processes and maintain its structure without the help of the cytoskeleton.
Comments
Keep subjects together
You have two sentences that talk about dynamic instability, but they are separated by a sentence about microtubules and actin. Both your dynamic instability sentences make reference to "these structures", so you may consider explaining the comonents of the cytoskeleton being actin and myosin and then grouping the sentences about dynamic instability together.
Rather than introducing
Rather than introducing dynamic instability by name first, I suggest describing its function then explaining that this is what the process is called. For example you could say "The ability for these structures to polymerize and depolymerize is a function known as dynamic instability." of course you could go more in depth about the process following that.