Final answer:
Organisms that cause disease are referred to as pathogens, which can lead to infectious diseases that are transferable between hosts. Acute diseases have a rapid onset, whereas chronic diseases continue for an extended period.
Step-by-step explanation:
Organisms that cause disease are called pathogens. Pathogens are agents, usually microorganisms, that can lead to diseases which are termed infectious or communicable because they can spread by moving from one host to another.
Infectious diseases, such as the common cold and influenza, are caused by different types of pathogens, including bacteria, viruses, fungi, and protozoa. Acute diseases have a rapid onset and typically a short duration, while chronic diseases have an extended period of illness.