Select from:
(a). PDAs.
(b). humans.
(c). viruses.
(d). crocodiles.
(e). animals.
(f). sharks.
(g). fur seals.
(h). insects.
Q: You are presented with the quiz "What have similar membranes?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "some viruses have an envelope of phospholipids and proteins" and "viruses are enveloped by similar membranes". So, what's the best answer to the question?
A:
(c).