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.
US Population to Hit 324 Million in 2016, 400 Million in 2050. The U.S. population is aging, and is moving away from one which is largely descended from people who came from Europe and more toward people from Central America, Mexico, and Asia. And, the rate at which the U.S population is growing has stagnated. There will be 323,996,000 Americans in 2016, barely up from 321,369,000 last year and slightly less than 326,626,000 in 2017. The U.S. population will not reach over 400,000,000 until 2051, when the Census forecasts it will reach 400,124,000.