Answer:
E. Cytoskeleton present.
Explanation:
The cytoskeletal structure in the cell was not present in the Last universal common ancestor (LUCA) but it appeared later by symbiogenesis apparently from aerotolerant spirochetes in the Proterozoic Eon. An event of eubacteria–archaebacteria symbiosis would have allowed the formation of the cytoskeleton and also of the nucleus of eukaryotic cells.
