Useful satellite data concerning sea ice began in late 1978 with the launch of NASA's Scanning Multichannel Microwave Radiometer (SMMR) satellite.
Answer:
Arithmetic Density
Explanation:
it is the total number of people divided by the total land area and this is just talking about population density not the amount of arable land (physiological density) or comparing the number of farmers to the area of arable land (agricultural density)
They are connected by the Northern European plain
