Flatworms belong to endoparasites and live inside other animals. They move through the intestines of the host animal and live at the expense of nutrients coming from food. They do not have their own organs for getting food. Flatworms are hermaphrodites, they are both males and females at the same time. They multiply themselves, laying eggs or simply dividing in half. Flatworms have a long and flat shape. They do not have a blood circulatory system. Some of them do not even have an intestine. The length of flatworms can vary from one millimeter to 30 meters.
2. Coral Polyps
With the help of tentacles, coral polyps can catch various small animals. Like plants, they can be fed by photosynthesis, carried out by unique unicellular algae, which are embedded in the structure of coral cells. These algae perceive light and form nutrients consumed by coral polyps.
Nautilus pompilius lives at a depth of 400 meters in warm sea waters near the seashores of Australia, China, Indonesia, the Philippines. Its ancestors lived in the World Ocean more than 500 million years ago
Jellyfish have no blood, skeleton, and fangs, but they are called sea predators. Their numerous tentacles are poisonous. Moreover, one jellyfish has more than 20 eyes which monitor passing animals. When a prey approaches, the jellyfish strikes it with its poison, which has a paralyzing effect and pulls it to the mouth with its tentacles.