Humans have species resistance to feline immunodeficiency virus for which of the following reasons?

Human cells do not have the chemical receptors required for attachment by feline immunodeficiency virus.
Feline immunodeficiency virus is a nonpathogenic virus.
Human phagocytes are extremely effective at eliminating feline immunodeficiency virus from the body.
Human cells produce a special type of interferon that protects against feline immunodeficiency virus.

Johannesburg kepler, an apprentice of brahe, believed in the heliocentric universe but rejected past astronomers belief in

Read the following scenario to answer the following question. in some zoos, rare crosses between a male lion and a female tiger have produced hybrid offspring called "ligers." male ligers are sterile but some female ligers are fertile. in the wild, lion and tiger ranges do not naturally overlap, making such a cross unlikely. furthermore, the solitary behavior of tigers and the social organizations of lions create behavioral differences. applying the biological species concept, the sterility of ligers reveals that a. lions are probably a subspecies of tigers b. tigers and lions are the same species c. a new species called "ligers" is forming d. tigers and lions are separate species

If bacteria are much too small to see, what is one reason why can we see colonies in the petri dishes that have plenty of food to eat after only a few days?