Leaches are parasitic segmented worms that live in oceans, rivers, and streams. There are more species of insects than all other animal speices combined. They all have a head, thorax. and abdomen. The thorax has three pairs of legs and often one pair of wings. Most flowering plants are pollinated by insects.
Fleas are parasites on warmed-blooded vertebrates.
Usually their body is covered with scales and coated with slime. Jawless fish have a long tube like body and a sucker mouth, no jaw, and no fins. Cartilage fish have a skeleton of cartilage and a jaw. Cartilage fish such as sharks have fins. The eggs are immediately fertilized by the male.