The two solstice’s happens around June 20th or 21st
The Equinox happens in March (about March 21st and September 23rd
Explanation; These are the days when the Sun is exactly above the Equator, which makes day and night of equal length.
The Sun Belt is the area south of the US, that stretches across the Southeast and Southwest, roughly south of the 36th parallel. It is characterized by mild weather and fast economic growth.
The area has seen an increase in immigration since the 1960s, although immigration had been high for decades before that. For example, in the period from 1900 to 1965, the population of California grew from fewer than one million to the greatest in the Union.
Several challenges have arisen from the influx of workers into the Sun Belt. Problems with resources, and in particular water supply, are threatening to the south, as the semi-desert weather is predominant.
Another problem is housing. The price of properties have increased dramatically, as many of the US larger cities are located in this area.
A theory is a hypothesis that is proved to be true through rigorous scientific methods of verfiication, mathematical and scientific arguments. Theories escalate into laws more when found out to be a natural fact. In this case, the answer would have to be A.