Elephantiasis is a common condition caused by roundworms; peoples' feet and legs swell up from roundworms blocking the flow of lymphatics. Roundworms can shed their skin and move in soil by a push-and-pull movement of their muscles. They have a digestive system and very primitive excretory and nervous systems.
Answer:
mollusks.
Explanation:
Mollusks and other soft-bodied animals as jellyfish or worms may be preserved as carbonaceous films in black shales.
These animals generally have a body divided into: head, foot and visceral mass. The sense organs are found in the head. The foot is responsible for the movements and, in some animals, like the octopus, it can be replaced by the tentacles. The visceral mass is where all the organs are located.
