Question

An organism which harbors a pathogen and may pass it on to another person to cause a disease is known as:
(a) Host
(b)Vector
(c)Parasite
(d)Predator

Answer 1

An organism which transmit infectious pathogen on to the another person or animal to cause a disease is called Vector.

To understand it clearly, we must be familiar with all other terms.

• Host - An organism that is infected by other parasitic or pathogenic organism.
• Parasite - A smaller organism that resides over the body of a larger organism but it doesn't cause direct death to the other organism.
• Predator - A smaller or larger organism which prey on other organism with a motive to kill the organism.

Answer 2

Host is the organism which harbours pathogen and can infect other individual.

Explanaion:

• An organism harbouring a parasite or any pathogen is known as a host.  
• The host is important because it act as a reservoir and source of pathogens.
• Some pathogens also depends upon the host (or multiple host) to complete its life cycle.
• The host can be classified into two types : 1. Definitive @. Intermediate.
• The pathogen can easily spread from one host to another by means of direct contact, eating the infected host, etc.