Why is a pathogen generally more virulent in a new habitat?
A) More pathogens tend to immigrate into newer habitats.
B) Intermediate host species are more motile and transport pathogens to new areas.
C) Pathogens evolve more efficient forms of reproduction in new environments.
D) Hosts in new environments have not had a chance to become resistant to the pathogen through natural selection.
E) New environments are almost always smaller in area so that transmission of pathogens is easily accomplished between hosts.
Answer: D - hosts in new environments have not had a chance to become resistant to the pathogen thru natural selection