available to them. Some flowering desert plants are ephemeral; they live for a few

days at most. Their seeds lie dormant in the soil, sometimes for years, until a

soaking rain enables them to germinate and quickly bloom. Woody desert plants

either have long root systems that reach deep water sources or have spreading

shallow roots that are able to take up surface moisture quickly from heavy dews

and occasional rains. Desert plants usually have small leaves. This conserves water

by reducing surface area from which transpiration can take place. Other plants drop

their leaves during the dry period. The process of photosynthesis—by which

sunlight is converted to energy and usually conducted primarily in leaves—is taken

over in the desert by the stems. A number of desert plants are succulents, storing

water in leaves, stems, and roots. Thorns, which are modified leaves, serve to

guard the water from animal invaders. These plants may take in and store carbon

dioxide only at night; during the day their stomata, or pores, are closed to prevent

evaporation. Desert plants growing on saline soils may concentrate salt in their sap

contrast, air sinks in the polar regions. This leads to high atmospheric pressure, and

sinking near the poles. Thus, the equatorial belt tends to be a region of low pressure

mild, moist winds that tend to bring frequent cyclonic precipitation to all elevations

and southerly components of the atmosphere's circulation. Thus, the tropical and

The vast majority of species are woody (see Xylem). Roughly between 80 and 200

phenomena were little understood until the advent of such advanced technology as

the pole in each hemisphere. To understand them, the circulation of the upper

of climate changes over geologic time is the province of paleoclimatology, which

microclimate, for example, can be specified that is good for growing plants

influenced by the complex structure and composition of the atmosphere and by the

Some common words found in the essay are:
Xylem Roughly, Rain Forest, ZONES Climates, , North South, Africa Tropical, rain forests, desert plants, South America, tropical rain, tropical rain forests, rain forest, upper canopy, winds tend, trade winds, moist air, northern hemisphere, climate long-term,
Approximate Word count = 1283
Approximate Pages = 5 (250 words per page double spaced)