Britannica Student Encyclopedia - 2010

Alps run along the border between

France and Italy.

The highest peak in the Alps is Mont

Blanc in France, at 15,771 feet (4,807

meters). Several other high peaks are

located on or near the Swiss-Italian border.

They include the Matterhorn.

The Alps receive a great deal of snow

and rain. At high elevations, the snow

turns to ice and then flows down to the

valleys as glaciers. Sometimes masses of

snow rush uncontrolled down the

mountainsides. These events, called

avalanches, endanger Alpine

communities. The clear Alpine lakes are

noted for their beauty. Among the most

prominent are Lakes Geneva,

Constance, Como, and Zurich.

The Alps are nearly treeless near the top,

but forests grow below. The higher forests

have mostly spruce, pine, and larch

trees. Oak, beech, and chestnut trees

grow on the valley floors and lower

slopes. A few kinds of animals have

adapted well to living in the higher

mountains. These include the ibex, the

Alpine marmot, and the mountain hare.

Humans have lived in the Alps since

prehistoric times, 50,000 to 60,000

years ago. German cultures developed

in the eastern Alps, while Roman

culture influenced the west. Some areas

of the Alps were cleared of forests

during the Middle Ages (500 to 1500).

Farmers settled the land, planted crops,

and raised cattle. During the 1800s,

railroads were constructed, opening up

the area.

Many people began to travel to the Alps

during the 1900s. Air, auto, and rail

transportation to the Alps improved,

making it easier for people to get there.

Today entire villages lodge, feed, and

entertain tourists. Popular resorts

include Innsbruck, Austria; Grenoble,

France; and Saint Moritz, Switzerland.

#More to explore

Avalanche • Europe • Mountain

The Matterhorn is one of the tallest peaks in

the Alps.

90 Alps, The BRITANNICA STUDENT ENCYCLOPEDIA

 

Alzheimer’s

Disease

Alzheimer’s is one of the most destructive

diseases of old age. The disease

destroys nerve cells in the brain. As a

result, the brain stops working correctly

and the memory is affected. Most

people who have Alzheimer’s disease are

more than 60 years old. Some people,

however, get it before that age.

The symptoms, or signs, of Alzheimer’s

disease begin mildly and then become

more severe over time. At first, people

with Alzheimer’s seem forgetful. Gradually,

they lose their entire memory.

People with Alzheimer’s also have a hard

time speaking and understanding other

people. They may not even recognize

close friends and family, such as their

own children. Eventually, they lose control

of body and mind.

Scientists are not sure what causes the

death of nerve cells in the brains of

people with Alzheimer’s disease. They

think the cause might be a genetic

defect. This means there might be a

problem with one of the genes that is

passed from parent to child. Because the

cause is unknown, there is no way to

prevent or cure Alzheimer’s disease.

Medications help to slow the disease in

some patients.

Amazon River

The Amazon is the mightiest river in

South America. It carries more water

than any other river. It is about 4,000

miles (6,400 kilometers) long. Only the

Nile River in Africa is longer.

The Amazon begins in the Andes

Mountains in Peru. From there it flows

north and then east through Brazil. It

empties into the Atlantic Ocean. The

Amazon drains about one third of South

America. This area includes most of

Brazil and Peru and parts of Bolivia,

Ecuador, Colombia, and Venezuela.

Plants and Animals

The Amazon region is the site of the

world’s largest rain forest. Its plant and

animal life is remarkably rich. Almost

three fourths of all the types of plants in

the world grow there. The animals

include monkeys, anteaters, anacondas,

toucans, and huge rodents called capybaras.

The flesh-eating piranha is among

the river’s many fish.

People

Millions of Brazilians live in cities in the

Amazon region. Belem, Manaus, and

Santarem are large, growing cities.

The Amazon

River carries

about 10 times

as much water

as the Mississippi

River.

BRITANNICA STUDENT ENCYCLOPEDIA Amazon River 91

 

At one time almost 7 million Indians

lived in the Amazon region. Europeans

arrived in the 1500s. They took many

Indians into slavery and removed them

from Brazil.Other Indians died from

diseases carried by the Europeans. In the

1990s there were about 600,000 Indians

in the Amazon.Most live in remote areas.

Economy

The countries of the Amazon region

have encouraged businesses to use the

resources found there. Mahogany, Amazonian

cedar, and other trees are cut

down for their wood. Rubber is another

valuable plant product. Diamonds, gold,

and oil are mined.

Many people have become concerned

about the effects of economic development

in the Amazon. Scientists warn

that destroying parts of the forest threatens

the plants and animals that live there.

#More to explore

Brazil • Rain Forest

Amber

Amber is a hard, yellowish, and often

see-through substance that formed from

tree resin. Resin is a thick fluid that

oozes from pine and fir trees when their

bark is injured.

The resin that formed amber came from

trees that grew millions of years ago.

Over time these trees and their resin