There is a digestive cavity in the center of the body, with a mouth but no anus. The tentacles have stinging cells that shoot venom. Common animals: hydra, sea anemone, jellyfish, coral

The body is flat and the digestive tract has an opening but no anus. Common animals: planarians, tapeworms, flukes, etc.

The body is mostly slender, linear, unsegmented, and has a mouth and anus in the digestive tract. Common animals: roundworms, filarial worms, rotifers, etc.

The body is composed of many similar body segments from front to back; movement is assisted by setae or warts. Common animals: earthworms, leeches, lugworms, etc.

The soft body surface has a mantle, mostly with shells; the locomotive organs are feet. Common animals: squid, octopus, snail, scallop, abalone, etc.

The body is segmented, with a hard exoskeleton and segmented appendages. Common animals: butterflies, shrimps, crabs, spiders, centipedes, etc.

The body is mostly streamlined; the body surface is covered with scales; it breathes with gills; it swims through the swing of the tail and trunk and the coordination of the fins. Common animals: carp, silver carp, hairtail, large yellow croaker, etc.

The larvae live in water and breathe with gills; most adults live on land and breathe with lungs, with exposed skin that assists breathing. Common animals: frogs, toads, giant salamanders, newts, etc.

The body surface is generally covered with scales or armor, and eggs are laid on land. The surface of the eggs has a hard egg shell. Common animals: hawksbill turtle, python, alligator, gecko, etc.

The body is mostly streamlined, the forelimbs turn into wings, and the body temperature is constant. The eggs laid by birds are generally larger and have hard egg shells. Common animals: parrots, mandarin ducks, chickens, ducks, geese, etc.

The whole body is covered with hair, the body temperature is constant, viviparous and lactating, and the brain is developed, making it the most advanced group in the biological world. Common animals: whales, elephants, dolphins, bats, etc.

There is no formed nucleus, the nucleoplasm is exposed, there is no nuclear membrane coating, and reproduction occurs by division. parasitic or saprophytic life

Common bacteria: Staphylococcus aureus, Bacillus subtilis, Helicobacter spp.

Similar to plant cells, it has no chloroplasts, relies on readily available organic matter, and lives a parasitic or saprophytic life.

Common yeasts, Rhizopus, mushrooms, Penicillium, Aspergillus, etc.

Composed of a protein shell and internal genetic material, parasitic in living cells

Divided into bacterial viruses, plant viruses, animal viruses

Simple structure, no differentiation of roots, stems and leaves

There are differentiation of stems and leaves, there are rhizoids, and the leaves are composed of a single layer of cells.

The differentiation of roots, stems and leaves has conductive tissue

Seeds are naked and not covered by pericarp

Seeds are coated with pericarp