An organism that carries a pathogen is called a
a. pathogen
b. contaminant
c. fungus
d. vector

d. vector

Explanation:

Biological vectors: These are all those organisms in which some essential phase of the life cycle of the pathogen takes place and they are able to transmit it actively to man and animals, either by bite, bite or through urine or feces. . This is the case of mosquitoes, triatomas, rodents and others.

Many of these vectors are hematophagous insects that ingest pathogenic microorganisms along with the blood of an infected carrier (person or animal), and then inoculate them to a new carrier by ingesting their blood.

Mosquitoes are the best known vectors, although ticks, flies, sandflies, fleas, triatomines, rodents and some freshwater snails are also found.

In the case of mollusks, these behave as intermediary hosts: those organisms in which one or several phases of the causal agent's life cycle take place, but do not actively transmit it to man and animals, but rather constitute vectors Liabilities of the disease.

condenser is used to focus in the light microscope.