When, where, and by whom were vaccines for polio developed? which vaccine is most effective, and why?

Jonas Salk. Jonas Edward Salk October 28, 1914 – June 23, 1995 was an American medical researcher and virologist. He discovered and developed one of the first successful polio vaccines. He discovered it in  Pittsburgh

though africans landed with few possessions, they carried their cultures, skills, and spiritual worldviews into the americas. wherever african religions took root in the new world, africans and their descendants changed and adapted their belief systems to local circumstances and influences. individual circumstances created variations in the way people practiced their faiths, what they believed, and what significance it held for their lives.

explanation:

mark brainliest!

in the 1800s, chinese workers migrated to the united states, first to work in the gold mines, but also to take agricultural jobs, and factory work, especially in the garment industry. chinese immigrants were particularly instrumental in building railroads in the american west, and as chinese laborers grew successful in the united states, a number of them became entrepreneurs in their own right. as the numbers of chinese laborers increased, so did the strength of anti-chinese sentiment among other workers in the american economy. this finally resulted in legislation that aimed to limit future immigration of chinese workers to the united states, and threatened to sour diplomatic relations between the united states and china.