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:)
Answer:
this one`s been up for debate for awhile now.
1. it depends on the organism
learning about an organism could be considered 'easier' to study in different ways. for example, if you are studying marine life, you will most likely have to keep it in a water habitat to watch it alive. If you are studying a land species, then watching from it`s natural habitat will give you more accurate results. sometimes the environment can affect an organisms internal systems more than you may think. this leads into my second point.
2. it depends on what you are trying to study
if you are trying to learn about the mating process, seasonal activity, migration, or external behavior, then monitoring it from it`s natural habitat or an area that is a close copy is your best option. but if you are looking into studying internal organs/systems or cells, then in <em>most</em> cases, the organism will need to be taken out of its natural habitat. only in very careful situations is it left in a habitat during examination.
The answer is true, they are only single celled!
Genetic
since we are made from our dna