Here's why:

* Parasitism: A relationship where one organism (the parasite) benefits at the expense of another organism (the host).

* Free-living: An organism that does not depend on another organism for survival. It obtains its food and resources independently.

Examples of free-living organisms:

* Plants: Photosynthesize to make their own food.

* Animals: Hunt, graze, or scavenge for their food.

* Bacteria: Decomposers, producers, or symbiotic relationships.

There are many other ways to classify organisms besides parasitic or free-living. For example, you might categorize them by:

* Kingdom: Plants, animals, fungi, bacteria, protists

* Habitat: Land, water, air

* Diet: Herbivores, carnivores, omnivores, detritivores

* Mode of reproduction: Sexual, asexual

Let me know if you'd like more details about any of these categories!