you feed your dog every time you come home from school at night. one day your afternoon classes are cancelled and you come home early. your dog barks for food, even though it is not her dinnertime yet. in this scenario, the is the neutral stimulus, and the is the unconditioned stimulus.

arrival home, food

Explanation:

When an unconditional stimulus is paired with a stimulus which was previously neutral the unconditional stimulus becomes a conditioned stimulus.

Coming home was a neutral stimulus but when it was paired with the unconditioned stimulus of giving food it became a conditioned stimulus. So, later on when you arrive the dog wants food irrespective of the time.

These are the concepts of classical conditioning.

because he was a christian?

the invasive species was introduced due to commercial purpouses, as there was a demand for fur clothes and hence, a business opportunity connected to this product. actually, it was when the nutrias scaped, causing harm to the us ecosystems when they acquired the status of invasive species. in this case they have caused an environmental problem, but it could have affected also economic interests or even human health.