Ms. Dung Purple - Unit 9: Protecting the Environment - Reading

Water pollution ___(1)___ ______ one of the biggest threats to the environment today. There are several sources of water pollution ranging from sewage and (___(2)___ ______ to soil erosion. The impact of water pollution on wildlife and their natural habitat can be immense. There are also a number of things that the average person can do to help stop water pollution.
We should conserve the soil ___(3)___ ______ soil conservation influences water pollution through erosion. As soil is eroded by water, it transfers sediment from the land to the body of water, which is polluted by the chemicals in the sediment. Phosphorus and industrial (___(4)___ ______ can be pulled into water through soil erosion. When phosphorus levels in water become too high, they can lead to algae blooms that can ___(5)_________ massive fish deaths and make water unsafe for human use. The best way to prevent soil erosion is to keep the banks of rivers well-covered with plants or trees. Planting trees can have a significantly positive impact on the reduction in soil erosion.

Large animals that inhabit the desert have evolved many adaptations for reducing the effects of extreme heat. One adaptation is to be light in color, and to reflect rather than absorb the Sun’s rays. Desert mammals also depart from the normal mammalian practice of maintaining a constant body temperature. This is an advantage since the heat of the first few hours of daylight is absorbed in warming up the body, and an excessive build up of heat does not begin until well into the day.
Another strategy of large desert animals is to tolerate the loss of body water to a point that would be fatal for non-adapted animals. An equally important adaptation is the ability to replenish this water loss at one drink. Desert animals can drink prodigious volumes in a short time, and camels have been known to imbibe over 100 liters in a few minutes. A very dehydrated person, on the other hand, cannot drink enough water to rehydrate at one session, because the human stomach is not sufficiently big and because a too rapid dilution of the body fluids causes death from water intoxication. The tolerance of water loss is of obvious advantage in the desert, as animals do not have to remain near a water hole but can obtain food from grazing sparse and far-flung pastures. Desert-adapted mammals have the further ability to feed normally when extremely dehydrated, it is a common experience in people that appetite is lost even under conditions of moderate thirst.