a) cytoskeleton as it's responsible for formation of spindle filaments during cell division
Technally the Earth experiences global warming all the time .... so the exact number is undefined
During endocytosis the plasma membrane folds inwards either through phagocytosis for solits or pinocytosis for liquids.
During exocytosis vesicles for the inside of the cell fuse with the membrane and are released outside of the cell.
