An organism's potential to produce disease in a person depends on four factors: the number of organisms, the person's immune sys
tem, the length and intimacy of the contact between the person and the microorganism, and the organism's _____________, or ability to cause disease., or ability to cause disease.
An irregularly occurring and complex series of climatic changes affecting the equatorial pacific region and beyond every few years, characterized by the appearance of unusually warm, nutrient-poor water off northern Peru and Ecuador, typically in late December
