The first mask was made in 7000 BC. It was used primarily for rituals and ceremonies and where typically made of leather or wood. Keep in mind, these where the first masks that our modern generation has been able to find and preserve, masks could have been made earlier than this but detirriorated over time.
However, the first modern surgical masks where made in the early 1960s and replaced a more primitive method of cloth masks.
I hope I have helped! :)
One of the Important reasons for the 1836 Specie Circular was the uncontrolled land speculation in the West. Real estate speculation was funded by increased availability of credit from the Second Bank of the United States and new, reckless frontier banks
Hess's law allows you to find the net enthalpy of the magnesium combustion by adding the enthalpies of intermediate reactions. The <span>Hess's </span>Law<span> of Constant </span>Heat Summation states that<span> the total enthalpy change for the reaction is the sum of all changes</span> (no matter how many stages the reaction has).
Answer:
July 28, 1914 – November 11, 1918
Explanation:
World war one was July 28, 1914 - November 11, 1918
Answer:
Vietnam War, (1954–75), a protracted conflict that pitted the communist government of North Vietnam and its allies in South Vietnam, known as the Viet Cong, against the government of South Vietnam and its principal ally, the United States
Explanation:
