The vegetation of the world is aligned latitudinally in broad bands circling the globe. As the climate changes from the equador northward and southward,so too, does the vegetation. The rainforests of the equatorial band in the Nothern Hemisphere give way to temperate forests, which are replaced by coniferous forests, that in the north, are replaced by treeless arctic tundra.
Much more than temperature changes with altititude, but the vegetational banding pattern remains: tundra on the top s of mountains, coniferous in middle slopes, and deciduous forests at the base of mountains. Timberline, which is the limit that separates the tundra from the coniferous forests is at 10,000 feet in the southern Rocky Mountains, but at the Canadian border, is at 6,000 feet. Plants have tolerance ranges (of environmental conditions) in which they can survive. There are two factors of great importance to plants: temperature and precipitation. In the tropics there are over 40,000 species of vascular plants; in the forests of the southeastern United States are 5,000; in the Canadian artic, about 425.In conclusion tropical rain forests, for example, occur in the hottest, wettest regions of the world, deserts in the hottest, driest, tundra in the coldest, driest, and so forth.
Marzia Ena, 3^D, 16/11/16
HOW TO MAKE FIRE USING FLINT AND TUNDER
The principle of this method is based on the interaction of steel and flint by friction. Steel is struck against the sharp edge of a hard stone, and sparks form as the rock peels away tiny pieces of heated steel. The sparks are directed to the tinder bundle that has been prepared to accept them when they fall. The spark is then blown into flame. The disavantage of this method is that steel is difficult to find in the wild. As indicated by the name, you need flint and a piece of steel to start. For a flint and steel fire to be successful, you must use very fine, dry tinder. To strike a spark with flint and steel, you have to:
1) Kneel on the ground, place a tinder bundle in front of you, and crounch over the bundle. If you are using charred cloth, place a piece into the depression of the tinder bundle before you begin.
2) Hold the steel in one hand between your thumb and index finger.
3) Grasp the flint in the opposite hand with the sharpest edge toward the steel.
4) To generate sparks, strike the steel against the sharp edge of the rock. Use deliberate, powerful strokes, directing the sparks toward the tinder bundle.
5) When you see a spark fall into the tinder, immediately give a light puff of air onto the tinder bundle.
FLINT KNAPPING, WEAPONS AND TOOLS
Flint is a hard, tough chemical or biochemical sedimentary rock that breaks with a conchoidal fracture
One of the most common uses of flint by prehistoric people was in the making of arrowheads. They were hard, tough and very sharp. Flint is highly resistant to weathering and is often found as pebbles or cobbles along streams and beaches.
Flint has been used by humans to make stone tools for at least two million years.  The conchoidal fracture of flint causes it to break into sharp-edged pieces. Early people recognized this property of flint and learned how to fashion it into knife blades, spear points, arrowheads, scrapers, axes, drills, and other sharp tools using a method known as flintknapping. If these tools were broken or damaged in use, they were often reshaped into smaller tools of similar function.
The value of flint for making sharp tools was discovered and utilized by Stone Age people in almost every early culture located where flint could easily be found. Their survival depended upon having a durable material that could be used to produce sharp tools.
Marzia Ena 3D