Term
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Definition
| the region near the bottom of a pond, lake, or ocean |
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Term
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Definition
| the organisms that live at the bottom of the sea or ocean |
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Term
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Definition
an increase in the amount of nutrients, such as nitrates, in a
marine or aquatic ecosystem |
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Term
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Definition
a shallow zone in a freshwater habitat where light reaches the
bottom and nurtures plants |
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Term
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Definition
| all organisms that swim actively in open water, independent of currents |
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Term
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Definition
the mass of mostly microscopic organisms that float or drift freely in the
waters of aquatic (freshwater and marine) environments |
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Term
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Definition
an area of land that is periodically underwater or whose soil contains a
great deal of moisture |
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Term
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Definition
| a flowing network of rivers and streams draining a river basin |
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Term
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Definition
all the bodies of fresh water, salt water, ice, and snow that are
found above the ground |
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Term
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Definition
| the area of land that is drained by a water system |
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Term
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Definition
| a structure that is built across a river to control a river's flow |
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Term
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Definition
a process of removing salt from ocean
water |
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Term
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Definition
a virus, microorganism, or other substance that causes disease; an
infectious agent |
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Term
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Definition
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Term
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Definition
| an artificial body of water that usually forms behind a dam |
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Term
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Definition
| the breaking down of organic nitrogen molecules so that it returns to atmospheric Nitrogen (N2) |
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Term
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Definition
| The fixing of Nitrogen into a form that can be used by most organisms |
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Term
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Definition
the raising of crops and livestock for food or for other products that
are useful to humans |
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Term
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Definition
the variety of organisms in a given area, the genetic variation within
a population, the variety of species in a community, or the variety of
communities in an ecosystem |
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Term
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Definition
a calculation that shows the productive area of Earth needed
to support one person in a particular country |
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Term
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Definition
the study of the interactions of living organisms with one another and
with their environment |
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Term
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Definition
| the relation between two different species of organisms that are interdependent; each gains benefits from the other |
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Term
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Definition
science the study of the air, water, and land surrounding an
organism or a community, which ranges from a small area to Earth's entire
biosphere; it includes the study of the impact of humans on the environment |
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Term
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Definition
a law of economics that states that as the demand for a
good or service increases, the value of the good or service also increases |
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Term
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Definition
any natural material that is used by humans, such as water,
petroleum, minerals, forests, and animals |
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Term
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Definition
an undesirable change in the natural environment that is caused by the
introduction of substances that are harmful to living organisms or by excessive
wastes, heat, noise, or radiation |
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Term
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Definition
the condition in which human needs are met in such a way that a
human population can survive indefinitely |
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