PART A: Which of the following best describes a theme of the text?

A. Pride and vanity
B. Friendship and acceptance
C. Hate and intolerance
D. Fear and prejudice

A. Pride and Vanity

Explanation: Pride: is a feeling of satisfaction derived from one's own or others achievements: Vanity is an excessive pride in or admiration of one's own appearance or achievements,like; narcissism,self-love, self-admiration,  self-obsession, etc.

this null effect is caused by a weak manipulation and ineffective internal validity. in a scientific study, as the one dr. morimoto is trying to perfom, internal validity refers to the confidence placed in the cause-effect relationship and to how well an experiment is done and able to eliminate confounding variables.        

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.