If you cut a worm in two parts, will it generate two worms?

False.Both parts would move some seconds but, after that, only the longest part would generate a complete worm. The shortest would die quickly. So, don't kill worms, they aren't starfish!!                                              

What animal represents the 80% of all the terrestrial animals?

The answer is under our feet:this animal who represents the 80% of all the terrestrial animals,including humans,are the earthworm.The earthworms longest are from Australia.It's measure is 3 mettres.They are very useful animals because they remove the soil and they fertilize the soil.

Why the koala sleep more than twenty hours in a day?

The koala only gets up for have lunch and then sleeps and sleeps.The koala lives in the jungles of Australia and it eats usually eucalyptus.These leafs have got a little bit calories,so it means,little energy and the koala needs to sleep for not to spend his little energy.He doesn't get up for drink because the eucalyptus's leafs are 50% water.The meaning of the word koala is "someone who doesn't drink".