Although America fought in many wars since, World War 2 was the last time the nation declared war (actually against two nations at the time). One declaration of war with Japan, and one declaration of war with Germany. I hope this helped !!
Ethnicity can be influenced by the factor of scale and place. Many ethnic people have been known to gather in places close to each other, forming what’s known as an ethnic enclave. Ethnic people tend to stick closer together in certain places and different scales. An example of this would be China Town which is found in New York, where many Chinese and other asian people stick close together because of similar cultures and differences compared to Americans.
According to a continuous study conducted by the NASA's Goddard institute, the Earth's average global temperature has risen by 0.8 degrees Celsius or 1.4 degrees Fahrenheit since 1880. Since the beginning of the Industrial Revolution, the thermometer readings have risen continuously.