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Term Term description

Land forms or bedrock composed of, containing, or characteristic of calcium carbonate (CaCO3), calcium, or limestone.

calcium carbonate

A chemical compound (CaCO3) found in soil or bedrock in all parts of the world, and is the main component of shells of marine organisms, snails, pearls, and bird and reptile eggshells. It is a solid compound that dissolves readily in water can buffer acids.

Calvin cycle

A series of chemical reactions that occur as part of photosynthesis, in which carbon is broken away from gaseous carbon dioxide and fixed as organic carbon in compounds that are ultimately converted into sugars.

capillary action

The means by which liquid moves through the porous spaces in a solid, such as soil and plant roots due to the forces of adhesion, cohesion, and surface tension. Capillary action is the force by which water and dissolved nutrients move against gravity into the roots of plants.


An organic compound consisting of a ring or chain of carbon atoms with hydrogen and oxygen attached; examples are sugars, starches, cellulose, and glycogen. Carbohydrates are metabolized and used as energy and are used as building blocks for other molecules.


Carbon (C), the sixth most abundant element in the universe, is a critical component of all organisms. It is the backbone of organic molecules like proteins, carbohydrates and fats. Carbon is used as a fuel for human activities and is most commonly obtained from coal deposits, although it usually must be processed into a form suitable for commercial use. Three naturally occurring allotropes of carbon are known to exist: amorphous, graphite and diamond.

carbon cycle

The carbon cycle is one of the Earth's important biogeochemical element cycles. As it cycles through the carbon cycle, carbon can be transformed into many different molecular forms, and can be in solid, dissolved (liquid) or gaseous phase as it cycles through the atmosphere, biosphere and hydrosphere. As an example, carbon in the gaseous form of CO2 in the atmosphere can be taken up by a plant and through the process of photosynthesis transformed into a glucose molecule (C6H12O6). This carbon molecule, now in the biosphere, could be consumed by an animal and synthesized into a protein molecule within the animal's muscle. When the animal dies and its body is decomposed by bacteria and fungi, the carbon will move into the cells of the decomposers and eventually be respired as CO2 to reenter the atmosphere.

carbon dioxide

Known as CO2, carbon dioxide is the primary element that is released from human activities. The leading source of carbon dioxide emission is the burning of fossil fuels that are needed for transportation and energy. Since the Industrial Revolution began around 1750, human activities have contributed substantially to climate change by adding CO2 and other heat-trapping gases to the atmosphere.

carbon footprint

The total amount of greenhouse gases produced to directly and indirectly support human activities, usually expressed in equivalent tons of carbon dioxide (CO2).

carbon sequestration

The removal and storage of carbon dioxide from the atmosphere in carbon sinks (such as oceans, forests or soils) through physical or biological processes, such as photosynthesis.

carbon sink

The process of carbon (CO2) sequestration from the atmosphere by plants and subsequent long term storage as plant biomass and plant derived organic soils.


A compound containing the group CO3. Carbonates include minerals such as calcite and rocks such as limestone.


A substance or agent causing cancer. There are many naturally occurring carcinogens, but many industrially produced chemicals have been shown to be far more potent than most of those found in nature.

care for creation

The moral principle that calls for stewardship of the Earth in a way that preserves and protects the integrity of the natural world while making its fruits available for the legitimate needs of human beings.


Any placental mammal of the order Carnivora, typically having large pointed canine teeth and sharp molars and premolars, specialized for eating flesh. Any other animal or any plant that feeds on animals.

Catholic Social Teaching

The body of moral principles, goals, and virtues developed by the Catholic Church on matters of social justice involving issues of poverty and wealth, the organization and role of the state, cultural expression, religious freedom, and human rights.


An ion is an atom or molecule with a net electric charge due to an unequal number of protons (positive particles) and electrons (negative particles). Cations have a positive charge because they have more protons than electrons.

cellular respiration

The metabolic processes whereby certain aerobic organisms obtain energy from glucose, a 6-carbon sugar molecule. Oxygen is consumed and carbon dioxide is generated in the process.

chemical bond

An attraction between atoms that allows the formation of chemical substances that contain two or more atoms. These can be "strong bonds" such as ionic or covalent bonds, or "weak bonds" such as dipole-dipole interaction, hydrogen bonding, or London dispersion force.

chemical energy

Energy liberated by a chemical reaction or absorbed in the formation of a chemical compound. Each bond within a chemical compound involves different amounts of energy. When one of these bonds breaks, a chemical reaction occurs and chemical energy is used. The bond is released and is either reused in forming new bonds with other atoms or enters the surrounding atmosphere as heat.

chemical reaction

A process that leads to the transformation of one set of chemical substances to another.

chemical transformations

A process that involves changes in the structure and energy content of atoms, molecules, or ions but not their nuclei.


Organisms that make their own usable forms of energy from chemicals in the environment.

chemosynthetic bacteria

Bacteria that make food by chemosynthesis, which is the formation of organic compounds using the energy released from chemical reactions instead of the energy of sunlight. Bacteria living in aphotic areas of the ocean are able to survive by chemosynthesis. They use energy derived from the oxidation of inorganic chemicals, such as sulfur released from deep hydrothermal vents, to produce their food.

Chhath Puja

Chhath Puja is an ancient Hindu festival dedicated to the Hindu Sun god Surya.


Chlorophyll is a molecule that can use light energy from sunlight to turn water and carbon dioxide gas into sugar and oxygen (this process is called photosynthesis). Chlorophyll is magnesium based and is usually green.


A structure within a green plant cell in which photosynthesis occurs. Chloroplasts are distinguished by their green color, which results from the presence of two pigments, chlorophyll a and chlorophyll b. A function of these pigments is to absorb light energy, which is converted to chemical energy during the process of photosynthesis.


The religion based on the person and teachings of Jesus of Nazareth.



A fine-grained natural rock or soil material that contains one or more minerals and traces of metal oxides and organic matter. When clays are wet they are malleable and can be shaped by hand; they become hard and brittle upon drying or baking. Clays play an important part in maintaining soil fertility, making cations such as NH4+, K+, and Ca+ more accessible to plants' roots.


The composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years.

climate refugees

People who are forced to emigrate from their home region due to sudden or long-term changes to their local environment which compromise their well being or secure livelihood. Such changes include droughts, desertification, floods, intense storms such as typhoons and hurricanes, sea level rise, and disruption of seasonal weather patterns such as monsoons.


Climatologists study climate change, climate variability, and the effects of climate on the biosphere. They use computers to predict the effect of weather or climate on the growth and development of grain, vegetables, fruit, and other crops.


A substance, such as a metallic ion or a co-enzyme, that must be associated with an enzyme for the enzyme to function. Co-factors work by changing the shape of an enzyme or by participating in the enzymatic reaction.


The combustion of two different types of materials at the same time. One of the advantages of co-firing is that an existing plant can be used to burn a new fuel, which may be cheaper or more environmentally friendly.

coastal deserts

Coastals areas where cold upwelling seawater cools the air above the water and decreases its ability to hold moisture. Examples: Atacama Desert of coastal Peru, Namib Desert of coastal South Africa.



Molecular attraction by which the particles of a body are united throughout the mass, as, for example, with the cohesion of water molecules producing liquid water.

combustion reaction

Anytime anything burns, it undergoes a combustion reaction. Combustion reactions always involve molecular oxygen O2. When organic molecules combust the reaction products include carbon dioxide,  and water, heat and other elements or compounds that were contained within the fuel.


Goods or services that human beings buy or sell by means of rules and customs guiding their society's economic system.


Something of value that is bought and sold.

common good

The sum total of those conditions of the natural world and of humanity’s physical, social, and spiritual life which allow social groups and their individual members the relatively free and equal ability to achieve a fulfilled live.



A substance consisting of atoms or ions of two or more different elements in definite proportions that cannot be separated by physical means. A compound usually has properties unlike those of its constituent elements. Compounds can be molecules, salts, intermetallic compounds, or complexes.

condensation process

Condensation is the process by which water vapor in the air is changed into liquid water through cooling. Condensation is crucial to the hydrologic cycle because it is responsible for the formation of clouds. These clouds may produce precipitation, which is the primary route for water to return to the Earth's surface within the hydrologic cycle.


The transfer of heat from one molecule to another through a substance.


The protection, preservation, management, or restoration of wildlife and of natural resources such as forests, soil, and water.

continental drift

A scientific theory that asserts that all the continents on Earth were once connected, but have since drifted apart as plates on the Earth's crust move atop the Earth's liquid core.


continental interior desert

Extremely dry deserts in the continental interiors, far from source of moisture where hot summers and cold winters prevail; example: Gobi, Mongolia, Sahara.



The transfer of heat from one place to another by the movement of fluids.


The transfer of heat from one place to another by the movement of fluids.


The act or process of significantly changing from one state of mind, emotion, and behavior to another.


A fixed or firm belief.

coral reef

A mound or ridge of living coral, typically found in warm, shallow sea waters and rising to or near the surface. Coral reefs provide a critical habitat for a wide variety of fish and marine invertebrates, and protect shores against erosion by causing large waves to break and lose some of their force before reaching land.


The moral virtue of exercising strength for good purposes in circumstances of opposition.


covalent bond

A chemical bond created by the sharing of electrons between atoms.

crustal rocks

Rocks that form the crust of the Earth - igneous, metamorphic, and sedimentary.


Having the structure and form of a crystal; composed of crystals.


The process of formation of solid crystals precipitating from a solution, melted, or more rarely deposited directly from a gas.


Dominant mores of a society communicated through language, art, and education.


A group of photosynthetic bacteria (phylum Cyanobacteria) containing a blue photosynthetic pigment.


A crystalline amino acid (C6H12N2O4S2) that is widespread in proteins (as keratins) and is a major source of sulfur in protein synthesis.

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