Answer:
Changes in either the physical or biological components can alter the populations of many different organisms. These changes are called disturbances and can be either natural (volcanic eruption, drought) or man-made (increase in nutrient input by adding fertilizers, extinction of a species by habitat removal).
The temperate forest biome covers latitudes ranging approximately from the southern United States to southern Canada, while the taiga biome, also known as boreal forest, extends from the latitude of southern Canada to about 60 degrees north latitude. (see References 1, References 3) Thus, these two biomes are adjacent, which explains the many similarities between taiga and northern temperate forests. Both biomes have four distinct seasons, but the temperate forest climates cover a much wider range of temperatures and precipitation patterns. Taiga, in contrast, is reliably cold: most of the precipitation falls as snow, winters are severe and the growing season is short -- about 130 days compared to 140 to 200 days for temperate forests.
In a pervious rock, water may move through.
In an impervious rock, the impervious rock acts as a water barrier.
(A large block of pervious rock is an aquifer, a store of water)
By knowing which genes predispose people to particular conditions, doctors will be able to predict which people are likely to suffer from a particular disease and offer a preventive course of action, which may involve medical treatment or lifestyle changes. Furthermore, cures could be found for genetic diseases like cystic fibrosis or sickle cell anaemia. People could be diagnosed with illnesses that they are suspectible to develop in the future and spend their life worrying about it even before they get it.