<em>the following diagram explains it clearly:
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I think the answer is C. None of the other animals are mammals.
Scientists start with general observation and then make a hypothesis
Acute stress reaction results from experiencing an extremely difficult incident and has signs that occur immediately or shortly after the incident.
Acute stress reaction results from exposure to high-stress conditions. The signs and symptoms appear immediately or shortly after the incidence has happened and involves changes or reactions in physical, cognitive, behavioral and psychological functions.
The common symptoms that appear are anxiety, irritability, loss of appetite, depression, exhaustion, lack of energy etc.