Leukocytes are white blood cells
monocytes
Viruses and bacteria can be highly infectious.
A carrier is someone who harbors infectious organisms without having symptoms. Carriers together may represent a reservoir of pathogens.
Leukocytes
Leukocytes
Absence of microorganisms is sterile.
Leukocytes are part of the body, not separate organisms. As such they obtain their energy by metabolizing the sugars in the blood stream to produce needed energy. Strictly speaking, they do not "feed on" anything. They absorb and process sugars.
Shigella are extremely infectious bacteria, and ingestion of just 10 organisms is enough to cause severe diarrhea and dehydration.
Infectious disease
Infectious diseases involve a causative organism, from groups such as bacteria, viruses, fungi, and such. Noninfectious diseases involve causes other than specific infectious organisms.
To ingest invading microorganisms that have breached external defenses.
Which term describes body parts of different organisms that are similar in form?
Organisms or products of organisms that present a risk to humans