Lice, mites, and ringworm are examples of:

Lice, mites, and ringworm are classified as external parasites because they live on the surface of the host's body and derive their nutrients from it. External parasites can infest the skin and hair, leading to irritation and a range of other dermatological conditions.

Lice are insects that feed on human blood and can cause severe itching and discomfort. Mites, like scabies mites, burrow into the skin to lay eggs and feed, leading to inflammatory reactions. Ringworm, although classified as a fungal infection, is often included in discussions of parasitic infections due to its surface level invasion of the skin, leading to a lack of nourishment in the affected areas.

Conversely, internal parasites, such as certain worms or protozoa, inhabit the host's internal organs or bloodstream, which is not the case for lice and mites. Additionally, fungi are a separate group entirely and while ringworm is a fungal infection, the question pertains to the broader category these parasites fall under as living organisms that depend on a host for survival and nutrition. Bacteria, too, are fundamentally different microorganisms that are neither parasites in the context described nor share the same biological relationship with a host as lice or mites do.