What term describes organisms that grow and feed on other living organisms?

The term that describes organisms that grow and feed on other living organisms is External Parasites. These organisms extract nutrients from their hosts, often causing harm in the process. External parasites typically include entities such as lice, fleas, and ticks, which live on or in the host and can lead to various health issues, including irritation and transmission of diseases.

Understanding the nature of external parasites is important in esthetics because these organisms can affect the skin and overall health of clients. It is crucial to have knowledge of signs of external parasites to provide safe and effective treatments in a clinical setting.

The other options, while related to living organisms, do not accurately describe organisms that specifically feed off of other living hosts in the same way. For example, pathogens refer more broadly to any microorganisms that can cause disease, while fungi can live on decaying matter as well as living organisms, but not exclusively in a parasitic manner. Infectious agents are a general category that encompasses any microbes that can cause disease but does not specifically denote the feeding behavior on living hosts.