Final answer:
The Helmet Jellyfish is found in oceans worldwide, from surface to deep sea, and feeds on various organisms as a free-swimming medusae.
Step-by-step explanation:
The Helmet Jellyfish, a type of Scyphozoan, inhabits marine environments worldwide, including every ocean, from the surface to the deep sea. While some jellyfish are found in specific regions like the Great Barrier Reef, others have a more widespread presence. Jellyfish often live as medusae, the free-swimming stage of their life, during which they are solitary and carnivorous. They feed on a variety of organisms, including zooplankton, other invertebrates, and the eggs and larvae of fish. It is important to note that jellyfish, such as scyphozoans, have a life cycle that includes both a sexual medusoid phase and an asexual polypoid phase. Their complex digestive system, nerve net, and ability to swim illustrate the fascinating biological makeup of these creatures.