Temperature. Amounts of water available. Just to name a few
Both because they are vegetarian and they are reproducing more so they do have to compete for food
Answer:
amoeba made up one of the only cells.
Tapeworms belong to the Cestoidea class and the Platyhelminthes or flatworm phylum. Tapeworms are segmented and flat worms that are present in the intestines of a few animals. The Cestoidea class is a group of parasitic worms that belongs the flatworm phylum. All of the organisms included in this class are parasitic and live in digestive tracts. Humans do acquire these worms especially tapeworms when we eat meat like pork, fish and beef that is not cooked well. The largest species of tapeworm can be found in beef called the T. saginata. It could grow up to 20 meters or 65 feet.
I think the hydra lacks the specialized cells for touch and chemical detection. On the other hand earthworms have touch, light, vibration and chemical receptors along the entire body surface. Both of them are invertebrates (those animals without a backbone), they include insects, worms, jelly fish, spiders among other animals.