An indicator species<span> is an organism whose presence, absence or abundance reflects a specific environmental condition. </span>Indicator species<span> can signal a change in the biological condition of a particular ecosystem, and thus may be used as a proxy to diagnose the health of an ecosystem.
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Loss of habitat from human civilizations
B. An ecosystem in which plant roots are submerged during parts of the years
A : a car driving down a hill
A. prevent cross-contamination.
