Biodiversity ensures that there is a wide range genetic variations in certain species and many different species in an ecosystem. If an epidemic breaks out in a ecosystem if one species has some organisms that are immune to that disease they will survive and pass on the gene that makes them immune. If one species completely dies out in that ecosystem another species may be able to take over its role in the ecosystem so the whole ecosystem does not die out. If a certain species has a characteristic that helps them blend in with their environment and protects them from their predators those members of the species will survive and pass on their genes to later members of their species. If a invasive species is introduced it would be helpful if their was an animal in that ecosystem that could help regulate the invasive species population however what is most likely to happen is that due to the high stability of the ecosystem due to a high biodiversity the ecosystem will have a better chance of surviving because their will be different sources of food in the environment so the invasive species and the native species wouldn't have to compete too much for food.
She should have to classify this animal under pseudocoelomates category. The body cavity of these animals are filled with fluids. Internal organs are covered by the fluid filled space. The body cavity serves as the hydrostatic skeleton and have other functions such as digestion of food and waste removal.
