What type of parasites require living organic matter for survival?

The concept of parasitism is rooted in the dependency of certain organisms on their hosts for survival and reproduction. In this context, both strict parasites and obligate parasites fall under the category of those that require living organic matter.

Strict parasites are organisms that cannot survive without a host organism; they completely rely on their host for nutrients and are often unable to live independently. Examples of strict parasites include certain types of worms and viruses that must invade host cells to replicate and thrive.

Obligate parasites, similar to strict parasites, also require a host for their entire life cycle. These parasites have evolved to live in close association with their hosts, often leading to complex interactions that can include significant harm to the host. Many types of bacteria and protozoa are classified as obligate parasites because they cannot complete their life cycle outside of a host organism.

Both strict and obligate parasites are distinct in their reliance on living organic matter, as they cannot obtain the energy and nutrients they need from non-living sources. Thus, the identification of both groups as requiring living organisms for their survival solidifies the rationale behind selecting that particular answer.