Final answer:
Free-living flatworm species are predators or scavengers that hunt and consume small invertebrates or feed on decaying organic material. The correct answer for how a flatworm obtains its food is A. It hunts and eats other organisms.
Step-by-step explanation:
Flatworms are diverse creatures with varying dietary habits. The free-living species of flatworms are predators or scavengers. They primarily hunt and consume small invertebrates and can also feed on decaying organic material. Specifically, these organisms have a simple or branched gastrovascular cavity which functions in both the ingestion of food and the expulsion of waste. This means their "mouth" is also used as an anus, an efficient but basic system found in these simpler organisms.
In contrast, parasitic flatworms, like tapeworms, have no digestive system at all. Instead, they absorb digested food directly from the tissues or body fluids of their hosts. Nevertheless, many flatworms engage primarily in active hunting or scavenging for food rather than photosynthesis or filtering water.
Therefore, when considering the options provided in the query regarding how a flatworm obtains its food, the correct answer is A. It hunts and eats other organisms. This best describes the feeding behavior of most non-parasitic flatworm species.