Выбрать главу

(2008 estimate)

2,855,390—

rank, 32nd state

Capital

Little Rock

Area

53,179 sq mi

(137,732 sq

km)—rank, 29th

state

Statehood

June 15, 1836

Motto

Regnat Populus

(The People Rule)

State bird

Mockingbird

State flower

Apple blossom

BRITANNICA STUDENT ENCYCLOPEDIA Arkansas 181

 

Arm

Humans, apes, and monkeys have two

upper limbs called arms. Each arm

hangs from a shoulder and contains

bones, joints, and muscles. These parts

work together to give the arm a wide

range of movement. The arm can bend,

rotate, swing back and forth, and move

from side to side.

Structure

There are three bones in the arm. The

upper bone is called the humerus. The

top of the humerus fits into a cuplike

socket in the shoulder. Together they

make a joint that is held together by

tough strands called ligaments. This

joint allows the upper arm to swing and

rotate. A pair of muscles is attached to

the humerus. One muscle bends the

arm. The other muscle straightens it.

The lower end of the humerus connects

to a bone called the ulna at a joint in the

elbow. The ulna and another bone, the

radius, go from the elbow to the wrist.

This part of the arm is called the forearm.

A pair of muscles in the forearm

makes it twist from side to side. The

forearm ends in the hand.

Function

Humans, apes, and monkeys use their

arms and hands to push and pull objects,

to fight and defend themselves, and to

carry their young. Apes and monkeys also

use their arms to swing on branches and

to move around on the ground.

Arms in Other Animals

Many other animals have two front

limbs, but only primates have true arms.

The two front limbs of other animals are

known as legs, flippers, or wings. Both

starfishes and octopuses have limbs that

people sometimes call arms. But these

arms have no bones or joints. Starfish

arms are also called rays, and octopus

arms are also called tentacles.

#More to explore

Bone • Hand • Muscle • Primate

The human arm is similar to the front limbs

of other animals.

182 Arm BRITANNICA STUDENT ENCYCLOPEDIA

 

Armada, Spanish

The Spanish Armada was a fleet of ships

that Spain sent to attack England in

1588. The English defeated the Spanish,

which made Spain less powerful in

Europe.

The Armada sailed in May 1588 with

130 ships and 27,000 men. They

reached the English Channel in late July

and fought a few battles. On August 8

the English won a decisive victory. They

had fewer ships, but they had big guns

and could fire at long range. This was

unusual because at the time, sea battles

were fought at close range so that soldiers

could climb aboard enemy ships.

The defeat of the Spanish Armada saved

England from invasion. It also was the

first major gun battle at sea. For hundreds

of years afterward, gun-armed

warships ruled the seas.

#More to explore

England • Spain

Armadillo

Armadillos are small mammals related to

sloths and anteaters. They have a tough

armor that protects them from enemies

and other dangers. The word armadillo

is Spanish for “little armored one.”

There are 20 species, or types, of armadillo.

They live mainly in or near the

tropical (hot) regions of Central and

South America. One species lives in the

southern United States. Most species live

in open areas, but some live in forests.

Armadillos are stout with short legs and

strong, curved claws. They range in

length from about 6 inches (15 centimeters)

to 5 feet (1.5 meters). Armadillos

are usually brownish black with some

yellow markings. Their armor is a type

of hardened skin. It is made up of solid

plates and flexible bands. It covers most

of the body, including the head and usually

the tail.

Most armadillos have very little hair.

The pink fairy armadillo, however, has a

coat of soft, white hair on its underparts

and sides.

Armadillos are usually active at night.

They live in burrows, or holes that they

dig in the ground. Armadillos also dig to

find food. They eat mainly termites and

other insects, worms, roots, and small

animals.

Female armadillos usually bear one to 12

identical young. All develop from a

single egg inside the mother.

#More to explore

Anteater • Mammal • Sloth

The nine-banded armadillo is the only kind

of armadillo that lives in the United States.

Some types of

armadillo are

able to roll

themselves into

a ball to protect

their

underparts

from enemies.

BRITANNICA STUDENT ENCYCLOPEDIA Armadillo 183

 

Armenia

The Republic of Armenia is one of the

world’s oldest centers of civilization.

Yerevan, the capital, is also one of the

world’s oldest cities.

Geography

Armenia is located in western Asia,

between the Black Sea and the Caspian

Sea. It is bordered by Georgia, Azerbaijan,

Iran, and Turkey. Armenia is a

mountainous country. The Lesser Caucasus

Mountains stretch across the

north. Armenia’s highest peak, Mount

Aragats, is 13,418 feet (4,090 meters)

high. The area has experienced many

earthquakes, including one in 1988 that

killed some 25,000 people.

Armenia has a dry climate. Summers are

generally hot.Winters are generally not

very cold, except in the mountains and

on the windy plateaus.

Plants and Animals

Junipers, dog roses, and honeysuckles

grow in the lower areas of Armenia.

Thorny bushes cover the mountain

slopes. There are beech forests in the

northeast and oak forests in the southeast.

Among the animals found in Armenia

are wild boars, wildcats, jackals, Syrian

bears, lynx, ibex (a kind of wild goat),

and mountain sheep.

People

About 98 percent of the people are ethnic

Armenians. There are small numbers

of Kurds and other groups. Armenian is

the official language. Most people are

The Khor Virap monastery is an important

religious site for Armenians. It is associated

with Gregory the Illuminator. He introduced

Christianity to the Armenians more than

1,700 years ago. Behind the monastery

rises Mount Ararat, in Turkey.

184 Armenia BRITANNICA STUDENT ENCYCLOPEDIA

 

Christians of the Armenian Apostolic

church. Historically, the Armenian

church has been independent of both

the Roman Catholic and the Eastern

Orthodox churches.

Economy

Despite the growth of cities and industries,

agriculture is very important to

Armenia’s economy. Farmers raise potatoes,

wheat, tomatoes, barley, grapes,

watermelons, sheep, and cattle. Factories

make food products, metal products,

jewelry, machinery, chemicals, tobacco,

and textiles. Mines provide copper.

Transportation can be difficult because

of the mountains, but Armenia has a

network of roads and railways and an

airport.

History

Armenian civilization began as early as

the 500s BC. It reached its greatest size

and influence in the 1st century BC.

The Roman Empire conquered

Armenia in 30 BC. From the 300s to

the 1800s Persians, Byzantines, Arabs,

Mongols, Turks, Russians, and others

conquered and ruled Armenia at

different periods.

During 1895–96 Ottoman Turks killed

thousands of Armenians, who wanted

independence from the Ottoman

Empire. In 1915, at the beginning of