Zoonotic disease are perpetuated in nature by a single vertebrate species

Answer: Option B

Zoonotic diseases are perpetuated in nature by a single vertebrate species is by Direct zoonosis.
Zoonosis is an infectious disease that has jumped from non-human animals to humans. Zoonotic pathogens may be bacterial, viral or parasitic, or may involve unconventional agents and can spread to humans through direct contact or food, water or the environment.
Direct zoonosis may be perpetuated in nature by a single vertebrate species, such as dogs or foxes for rabies or cattle, small ruminants or swine for brucellosis.