What is an invasive species? they are plants/fungi/animals that isn't native to a specific area (an introduced species). They have the tendency to spread and cause damage too the environment, human economy, and/or human health. The Answer to your question is No. Not every species that is introduced to a specific area is invasive. The introduced species might have a natural predator that might eat it. The species may even be biologically, chemically, or mechanically controlled. I hope this helps you out:)
Mollusks
Mollusks is the group of invertebrates that made up the majority of the Marine species. Their bodies tend to not divided into segments like other organisms.
Grass and stuff they are herbivores
An animal can respond in negative ways such as: biting, scratching, urinating, whining, restlessness, snippy, or getting sick.