5. Sodium-potassium pump: Protein mechanism found along the neuron membrane which transports 3 Na+ ions outside of the cell while also drawing 2 K+ ions into the cell; this is an active transport mechanism (requires energy (ATP) to function). 6.
What Is the Population Density of the United States? The population density of the United States is approximately 87.4 people per square mile, according to the 2010 U.S. Census. What Is the Most Densely Populated Continent? Perhaps not surprisingly, the most densely populated continent is Asia. Here are the population densities of the continents: 1  North America - 32 people per square mile. 2  South America - 73 people per square mile. 3  Europe - 134 people per square mile. 4  Asia - 203 people per square mile. 5  Africa - 65 people per square mile. 6  Australia - 6.4 people per square mile.
Urban area: 20.6 million people Population density: 1,800 people per square kilometer. New York City, especially Manhattan, is arguably a role model for balancing urban development with good public transport and access to open spaces. New York is the only American city where most households do not own a car.