Ammonia is typically the primary form in which nitrogenous wastes appear in human urine. Vaccination has eliminated polio, a disease caused by a virus, from the Western Hemisphere. All vaccinated persons have memory cells that recognize polio virus antigens. Exposure of vaccinated persons to polio virus will induce a response from the specific memory cells that recognize polio virus antigens. Memory cells that recognize polio virus antigens can survive for decades in the body of a person vaccinated against polio.
Eukaryotic genomes consist of a. a single circular chromosome.
The physical position of a particular gene along a chromosome is known as its a. allele. When our defenses against disease are overwhelmed by infection, drug treatments can reduce the infection to levels that permit our own immune responses to cure us. Antibiotics are chemicals used as drug treatments by humans that are variations on natural compounds produced by bacteria and fungi as chemical warfare agents against a. viruses. Click here to return to the Biology 104 home page.