Which of the following needs a host to reproduce?

1) all of the above

2) eukaryotic cell

3) none of the above

4) prokaryotic cell

5) virus

A virus is not a living thing so antibiotics, intended to kill living things, are not effective. A virus cannot multiply outside a living host cell. There is no treatment for a virus, just supportive therapy. The body will fight off most viruses over the course of time. Vaccines do not cure viruses, so the only way to protect your goat from viruses is through specific vaccines.

So the answer is a virus