292Glossary
Alveoli Tiny sacs in the lungs through
which oxygen and carbon dioxide pass to
and from the blood.Altitude Height above sea level.Amphibian Cold-blooded vertebrate
such as a frog or newt.Apprenticeship Working under a skilled
craftsperson to learn a trade.Artifact Object made by human
workmanship.Arteries Blood vessels that carry oxygen-
rich blood away from the heart.Artificial intelligence A branch of
science that aims to create intelligent
machines.Astrolabe An ancient instrument used to
calculate the position of stars in the sky.Atmosphere The mass of air that
surrounds the Earth.Atoll A ring of coral reef surrounding a
central lagoon.Bacteria Single-celled microorganisms
that can be helpful or harmful.Big bang The cosmic explosion that
created the universe billions of years ago.Biodiversity The range of different
organisms that live in a particular area.Biofuel Any fuel made from biological
matter, such as plants or animal waste.Biome Any of Earth’s major ecosystems
with a particular climate and vegetation.Black hole A collapsed star in which the
pull of gravity is so strong that not even
light can escape it.Calligraphy The art of decorative
writing.Camouflage A color or pattern on an
organism’s body that allows it to blend in
with its surroundings.Canopy The uppermost leafy layer of a
tree or forest.Canyon A deep, narrow valley with steep
sides.Capillaries Tiny blood vessels that
connect arteries to veins.Carnivore An animal that eats only meat.Cells The building blocks of almost all
living organisms.Ceramic Any object made from clay and
hardened by heat.Chlorophyll The green pigment in
plants that helps them absorb sunlight for
photosynthesis.Chromosomes Packages of DNA found
inside the nucleus of most cells.Colloid A suspension of fine particles
dispersed in a liquid.Colony A group of organisms that live
together.Condensation The change of state from
a gas to a liquid or a liquid to a solid.Continent One of several large
landmasses on Earth.Climate The average weather conditions
over a long period of time.Cloning The process of producing
genetically identical animals or plants.Communism A political theory based on
the common ownership of property.Crystal A solid in which the atoms or
molecules from which it is made are lined
up in a regular pattern.Cubism A style of art that shows a scene
from several different points of view all
at once.Deities Gods and goddesses.Democracy A system of government in
which people elect their leaders.Diaphragm A sheet of muscle that
separates the lungs from the stomach.Dictator A ruler who has absolute power.GLOSSARY