Nathan "worries all of the time." he worries about his money, his parents, his friends, his grades, and his dog. his muscles are always tense and sore. nathan has trouble sleeping, is often irritable, and has difficulty concentrating. nathan's symptoms sound most like

Based on the given situation, the best answer for this would be:

Panic disorder

This is an anxiety disorder in which the fears of an individual are intense which leads to a sudden panic attack where the person has symptoms of palpitations, shaking and even difficulty in breathing.

i would say b probably

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.