Similar DNA may support "common" ancestry. ☺
I think the answer your looking 4 is B
HOPE THIS HELPS
#Optimist
The answer would be AUTOTROPHIC
If you're talking about eukaryotic cells then it's the cell wall. If it's a prokaryotic cell sometimes the slime layer secreted by some bacteria may harden and form a capsule around the bacterial cell.
Hope i helped!