Vertebrates have a back bone. They have living endoskeleton, pharnyx and efficient respiration, advanced nervous system, and paried limbs.
Most viruses reproduce through a process called lytic infection. During lytic infection, a virus enters the host cell, makes a copy of itself, and causes the cell to burst, or lyse.
Hope this helps :)
Answer:
My guess would be H₂O/ water, since osmosis is a form of passive transport and I can't see the model the question references. Gases like O₂/ oxygen, CO₂/ carbon dioxide, and simple sugars like glucose can also pass through a cell membrane with passive transport though.
