Answer:In 1947, Salk took a position at University of Pittsburgh, where he began conducting research on polio, also known as infantile paralysis. By 1951, Salk had determined that there were three distinct types of polio viruses and was able to develop a "killed virus" vaccine for the disease.
Explanation:
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Answer: B) Command</h3>
For instance, the government sets prices of all goods in a command economy and they also set the production level (ie how much of a certain item to produce).
A traditional economy is based on the culture and often uses the barter method. A market economy uses currency instead of bartering, and the prices are determined by market forces (ie the people in the market). A mixed economy is a combination of command and market.
An example of a mixed economy is the United States where free market forces determine prices though there are government regulations set up to ensure the economy doesn't go south, and to ensure fair trade practices are followed.
D. citizens could ask their government to address a particular grievance and that the government would take them seriously.
1. Make and study flash cards
2. Highlight anything that might be important and look over it daily
3. Donating clothes to a homeless shelter; makes you feel good and proud of yourself and helps the homeless have clothes on their back
4. You can organize a group to help pick up trash or start a protest to keep the environment clean
5. My bedroom because it creates a calm and peaceful environment
