Chооse the mаin pаttern оf orgаnization of the passage. The biological significance of a single sperm is very different from that of a single egg. For healthy men, sperm is a “renewable resource” produced by the testes throughout most of the life course. A man releases hundreds of millions of sperm in a single ejaculation, technically enough to fertilize every woman in North America. However, a newborn girl’s ovaries contain her entire lifetime allotment of immature eggs. A woman releases a single egg from the ovaries every month. Whereas men are biologically capable of fathering thousands of offspring, a woman is able to bear a much smaller number of children.
Chооse the mаin pаttern оf orgаnization of the passage. Heavy use of groundwater causes a regional water table to drop. In parts of western Texas and eastern New Mexico, the pumping of groundwater from the main underground water source has caused the water table to drop 30 meters over the past few decades. The lowering of the water table means that wells must be deepened and more electricity must be used to pump the water to the surface. Moreover, as the water is withdrawn, the ground surface may settle because the water no longer supports the rock and sediment. Mexico City has subsided more than 7 meters and portions of California’s Central Valley 9 meters because of extraction of groundwater. Such subsidence can crack building foundations, roads, and pipelines. Overpumping of groundwater also causes compaction and porosity loss in rock and soil, and can permanently ruin good aquifers.