Final answer:
An illness caused by biological infestation is an infectious disease, which involves pathogenic organisms multiplying within the host and causing harm.
Step-by-step explanation:
An illness caused by an infestation of the body by biological organisms is called an infectious disease. The correct answer to the question is A) Infectious disease. Infectious diseases occur when pathogenic microorganisms, such as bacteria, viruses, parasites, or fungi, enter the body and start to multiply, leading to damage or impairment of body functions. These pathogens can be transmitted from person to person, or sometimes, from animals to people (known as zoonoses). Examples of infectious diseases include the common cold, tuberculosis, and malaria. Infectious diseases can be acute, meaning they occur suddenly and last for a short duration, or chronic, where the diseases are long-term and may become a continual presence in the individual's life.
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