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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Since it has 4 protons, it must have an atomic number of 4. (That makes it beryllium.)
Since it has a 4 protons and 5 neutrons, it has a mass number of 9.
<span>They exhibit all the stages when its the presence of oxygen only.</span>
