Final answer:
Overpopulation is a root cause of environmental problems, leading to unsustainable resource use and habitat destruction, compounded by high consumption rates in developed nations.
Step-by-step explanation:
One of the root causes of environmental problems is A) Overpopulation. Overpopulation leads to a variety of environmental issues such as unsustainable resource use, habitat destruction, and the unsustainable fishing and hunting of wild animal populations. The excessive use of fossil fuels also contributes to climate change and a reduction in biodiversity. The environmental problems we face are not solely due to overpopulation; the high consumption rates and wasteful practices, particularly in developed nations, also exacerbate these issues. Addressing overpopulation, alongside reducing consumption and our ecological footprint, is necessary to mitigate these environmental challenges.