Monarchs in some constitutional monarchies, and presidents in semi-presidential republics are often considered to be figureheads. Commonly cited figureheads include Elizabeth II,[1][2] who is queen of 16 Commonwealth realms and head of the Commonwealth, but has no power over the nations in which she is not head of government and does not exercise power in her own realms on her own initiative. Other figureheads include the emperor of Japan and the king of Sweden, as well as presidents in a majority of parliamentary republics, such as the president of India, Israel, Bangladesh, Greece, Hungary, Germany, Pakistan. Some head of states in one-party communist states also have limited powers, such as President of China (when not simultaneously holding the CCP General Secretary and CMC Chairman posts).
The ability to rapidly reproduce HeLa cells in a laboratory setting has led to many important breakthroughs in biomedical research. For example, by 1954, Jonas Salk was using HeLa cells in his research to develop the polio vaccine.
The political issues that caused the most division in Washington, DC, as the United States moved westward in the 19th century, was whether each new state admitted to the Union would be "slave" or "free". The issue eventually resulted in the Civil War.
