Host organisms are living entities that provide a suitable environment for other organisms, such as parasites, viruses, or symbiotic species, to live and thrive. These hosts can be animals, plants, or even microorganisms. The relationship between the host and the organism can vary, ranging from beneficial to harmful interactions. In many cases, host organisms are essential for the survival and reproduction of the organisms that depend on them. For example, in the case of viruses, they require a host cell to replicate and spread. Similarly, parasites often rely on their hosts for nutrients and shelter, which can lead to various health issues for the host.