Most believe that getting to heaven
requires only faith in God, not any specific
actions. They think that each
believer, not just priests, can spread
God’s teachings.
Most Protestant churches hold worship
services on Sundays. Protestants perform
only two of the sacraments, or rituals,
practiced by Roman Catholics: baptism
and Communion.
History
In the 1500s some Roman Catholics
began to disagree with their church. At
first they wanted only to change, or
reform, parts of the church. Their movement
became known as the Reformation.
But the leaders of Roman
Catholicism strongly opposed such
changes. Soon some people broke away
to form new churches. Members of the
new churches became known as Protestants.
The first Protestant churches to
form were the Lutheran church, the
Church of England, and the Reformed,
or Presbyterian, churches.
Catholics and Protestants fought wars
over religion in the 1500s and 1600s.
Protestantism remained strong, however,
and spread throughout Europe and its
colonies.
In the 1600s and 1700s some Protestants
thought that Protestantism was
still too close to Roman Catholicism.
Some of them formed new Protestant
groups, such as Congregationalists, Baptists,
Quakers, and Methodists.
In the 1800s missionaries spread Protestantism
further in the Americas, Africa,
Asia, and Oceania. New Protestant
churches continued to form in the
1800s and 1900s. Meanwhile, beginning
in the 1900s, some Protestants worked
to build unity with all Christians.
#More to explore
Bible • Christianity • Reformation
• Roman Catholicism
Protist
Protozoans, algae, and slime molds
belong to a group of living things called
A layer of slime mold covers leaves and a
wet log.
Three leaders
of the Reformation
were
Martin Luther,
John Calvin,
and King
Henry VIII of
England.
158 Protist BRITANNICA STUDENT ENCYCLOPEDIA
protists, or protoctists. Protists are not
animals, plants, fungi, or bacteria. Many
protists are so small that people can see
them only through a microscope.
There are thousands of different species,
or types, of protist. Many types live in
water, both in oceans and in freshwater.
Others live on land. Some, called parasites,
live inside the bodies of animals.
Some types are solitary—they do not
form groups with other protists. Other
types form groups called colonies.
Most protists are unicellular, which
means that they have just one cell. Some
protists are made up of clusters of cells.
But a protist never has more than one
type of cell.
Some protists act like animals. For
example, some types of protozoan move
around and feed on other living things.
Other protists act more like plants.
They make their own food through a
process called photosynthesis, just as
plants do. Many plantlike protists are
called algae.
The protists called slime molds can act
like animals or like fungi (such as mushrooms).
Sometimes slime molds move
around as unicellular creatures, as protozoans
do. But at other times slime mold
cells gather together. They form a slimy
layer that moves across forest floors or
other surfaces. This slime feeds on
decaying plants and other living things.
Sometimes small stalks grow out of the
slime. The stalks release spores, as fungi
do. These spores are tiny units that turn
into new slime mold cells.
#More to explore
Algae • Cell • Living Thing • Protozoan
Protozoan
Protozoans are simple organisms, or
living things. They belong to a group of
organisms called protists, which are neither
plants nor animals. Most protozoans
are so tiny that they can be seen only
with a microscope. Amoebas and paramecia
are types of protozoan.
Protozoans are found all over the world,
on land and in water. Protozoans living
on land especially like moist soil. Some
protozoans are parasites. They live inside
the bodies of animals, including
humans. Parasitic protozoans can cause
disease.
A protozoan is just a single cell. But it
can do all of the things that organisms
with many cells can. A protozoan can
The remains of a protozoan that lived long
ago are preserved in rock as a fossil.
BRITANNICA STUDENT ENCYCLOPEDIA Protozoan 159
eat, grow, reproduce, and get rid of
wastes. Most protozoans can move, too.
Protozoans have different shapes, but
they all have some features in common.
Like all cells, every protozoan is made
up of a jellylike material called cytoplasm.
Within the cytoplasm is at least
one nucleus. The nucleus directs the
functions of the cell. The cytoplasm also
contains special organs that do certain
jobs, such as digestion or making proteins.
Some protozoans have hairlike or
whiplike structures that help them
move.
Most protozoans reproduce themselves
without a partner. Usually the nucleus
pinches in the middle to create two
halves. The halves pull apart with equal
amounts of cytoplasm to form two separate
organisms.
..More to explore
Cell • Living Thing • Parasite • Protist
Providence
Population
(2000 census)
173,168;
(2007 estimate)
172,459
Providence is the capital of the U.S.
state of Rhode Island. It lies at the head
of Narragansett Bay, which is part of the
Atlantic Ocean.
Providence is a busy seaport. It is also
one of the main industrial centers in
