Salty foods are especially prone to microbial contamination due to their high water activity.
Deserts are most pronounced at 30 o latitude on the west sides of continents because of the wicking effect of warm air moving from the equator towards the poles. Tropical seasonal forests are dominated by broadleaf deciduous trees that drop their leaves in response to water stress. Tropical soils that support lush rain forests are generally nutrient poor. This solvent property is also responsible for the movement of water across membranes. Adaptation to environmental conditions is the key to survival of microbes, plants and animals.