Answer:
The cities have a much larger populations in smaller areas, which can cause more crime and overcrowding, along with pollution.
<span>B. short grasses and mosses
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D make ah model or a one of those
The main sources are humans which is why it is stated that the global warming is man made. The levels have increased beyond all measure, increasing since the 1950s by a 100 CO2 parts per million, and it keeps increasing by 2ppm on a yearly basis. The statistics from the industrial revolution era are not much different and show how much we've increased the CO2 in modern times.
