Which of the following was not a characteristic of luca?
a. genetic code based on dna.
b. only 20 amino acids used
c. enclosed by a lipid bilayer membrane.
d. atp was an energy intermdiate
e. cytoskeleton present.

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.

i think its white blood cells

i hope this