four pairs of spikes on its tail. The body
of Stegosaurus had an arched appearance.
Its back legs were longer than its front
legs. Stegosaurus had a small, narrow
head with a horn-covered beak.
Behavior
Stegosaurus was a plant eater. It used its
spiked tail and large plates to defend
itself. The plates contained blood vessels
that may have helped control its body
temperature as well. Stegosaurus most
likely lived in herds.
#More to explore
Dinosaur
Stock Exchange
A stock exchange, or stock market, is a
system for buying and selling securities,
or stocks and bonds. A stock is a share
in the ownership of a company. A bond
is an agreement to lend money to a
company for a certain amount of time.
Companies sell securities to people to
Stegosaurus
BRITANNICA STUDENT ENCYCLOPEDIA Stock Exchange 185
get the money they need to grow. People
buy securities as investments, or ways of
possibly earning money.
Many countries have one or more stock
exchanges. Some important exchanges
are the New York Stock Exchange (in
the United States), the London Stock
Exchange (in England), and the Tokyo
Stock Exchange (in Japan). These and
other exchanges do much of their business
in buildings. NASDAQ, in the
United States, is an exchange that does
its business electronically, or online.
How a Stock ExchangeWorks
A number of companies belong to each
stock exchange. The companies sell
securities to people. People then use the
exchange to trade (sell and buy) the
securities among themselves. The
exchange lists the securities for sale and
their prices. It also handles the transfer
of securities between sellers and buyers.
The prices of different securities rise or
fall, or both, throughout the day, every
day the exchange is open. People make
money by selling securities at a higher
price than they paid for them.
Rising and Falling Prices
Many factors affect the price of a
company’s securities. If a company is
successful, the price of its stock usually
will go up. The health of the economy,
laws passed by the government, and
wars also can cause securities’ prices to
rise or fall.
Even people’s feelings can affect prices at
a stock exchange. For example, if people
fear that prices will go down, they may
start selling their securities. But if many
people sell large numbers of securities,
they can actually make prices go down.
If widespread selling continues, a stock
market crash can happen. A crash means
that the prices have fallen so low that
very few people are willing to buy securities.
As a result, the people who own
the securities have little chance of getting
their money back.
Crash of 1929
A famous stock market crash happened
in the United States in October 1929.
Over several days panicked investors
sold so many shares of stock that the
market collapsed. Almost every part of
the economy suffered. Farmers could
not sell their crops, banks and businesses
closed, and wages fell to very low levels.
This period of hardship lasted about 10
years. It became known as the Great
Depression.
#More to explore
Economics • Great Depression • Trade
The New York Stock Exchange quiets down
after a busy day of trading.
186 Stock Exchange BRITANNICA STUDENT ENCYCLOPEDIA
Stockholm
Population
(2008 estimate)
795,160
Stockholm is the capital of Sweden, a
country in northern Europe. It is Sweden’s
largest city. It is also the country’s
center of government, culture, education,
and business.
Stockholm is known for its natural
beauty. It is located where Lake Malar
meets the Baltic Sea. The city is built on
many small islands as well as on the
Swedish mainland. Bridges connect the
different parts of the city.
The economy of Stockholm is based
mostly on industries that provide services
and on government. The city is a
center for banking, health care, education,
and research. Several companies in
Stockholm develop technology for computers
and wireless communications
equipment. Other companies develop
technology to make the environment
cleaner. Shipping goods through Stockholm’s
port is also an important industry.
Passenger ships use the port, too.
A Swedish ruler named Birger Jarl is said
to have founded Stockholm in about
1250. The city grew into an important
center of international trade.
For many years Denmark and Sweden
fought for control of Stockholm. In
1523 Gustav Vasa captured the city for
Sweden. Stockholm became the official
capital of Sweden in 1634.
Stockholm developed rapidly in the
middle of the 1600s. By the 1700s it
was a major center of the arts and sciences.
In the 1800s many streets, parks,
and buildings were constructed in
Stockholm. In the late 20th century
several new suburbs were created.
..More to explore
Sweden
Stomach
The stomach is a hollow organ that is a
part of the digestive system. Food lands
in the stomach after passing down the
throat through a tube called the
esophagus. The stomach stores food
and passes it along in small amounts to
the intestines.
Riddar Island is part of the oldest area in
Stockholm, Sweden. It is known for its historic
sites and architecture.
BRITANNICA STUDENT ENCYCLOPEDIA Stomach 187
The Human Stomach
The human stomach is located in the
