Final answer:
A carrier is an asymptomatic host that harbors a pathogen and can transmit it to others, potentially causing disease, unlike vectors which are organisms that actively spread pathogens.
Step-by-step explanation:
A carrier is a host with a pathogen that does not cause disease in the host but can be transmitted to others where it could cause disease. Unlike a vector, which is typically an organism like a mosquito or tick that actively transmits pathogens between hosts, a carrier is typically a human or an animal host that harbors a pathogen without showing symptoms of the disease. Carriers can unknowingly spread diseases to susceptible individuals through various modes of transmission, including direct contact or via contaminated food or water.