Ferdinand Magellan was the first (at least his crew) to successfully lead an expedition to circumnavigate the world. (he died on the voyage, but ~3 sailors made it back i believe, forgot the number of sailors, but very little)
hope this helps
The Seattle longitudinal study of cognitive development discovered that among older people (d.) higher socioeconomic status is associated with higher levels of intellectual functioning. Interacting socially and economically is a great factor in keeping up your intelligence up to date.
Technological advances increased profit and productivity
The Red Scare was a time in the US when Americans were worried and determined to protect the US from Communist influence and protect democracy and capitalism.
A because the ratio from black to white near close to equal