Humans can affect the environment in many ways, including air, water, land, noise pollution, soil erosion, global warming, oil spills etc.
Each of these factors affect the environment. For example, oil spills cut off supply of air to the underwater organisms thus causing problems in the environment.
Soil erosion causes reduced fertility of soil, meaning that trees/plants don't grow well. Global warming causes ice caps to melt, therefore, a rise in the water level of the oceans, impacting the environment of the world.
All these factors are caused by humans. Human ships and tankers spill oil in the emission. Increased emissions of greenhouse gases from factories and industries causes global warming. Soil erosion is caused by deforestation, i.e. cutting of trees to clear land. Even animals are killed for meat, hide, claw, skin or even simply for sport.
Thus, we can see that human activities greatly impact the environment in a negative way.
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