Answer:
A virus is a microscopic infectious organism that has the ability to recreate/replicate itself with nothing but the cells that are living in another organism. Viruses have the ability to infect anything, from plants to animals to humans. You have much more of a chance of this being fatal (to any of these life forms) if you have heart problems or vitamin deficiency.
A population is the amount of things belonging to the species that is alive. A species is just a speficic type of animal plant bug etc
How are we to know the answers without knowing about which groups the question pertains.
Endoparasite. This is because it lives inside the host.
