Answer: it reaches 50 feet :)
Explanation:
30+20=50
Answer:
were introduced into American geography in the 1920s by Carl Sauer
<span>An indicator species is an organism whose presence, absence or abundance reflects a specific environmental condition. Indicator species 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. For example, plants or lichens sensitive to heavy metals or acids in precipitation may be indicators of air pollution. Indicator species can also reflect a unique set of environmental qualities or characteristics found in a specific place, such as a unique microclimate. </span>
A contour line<span> or isoline </span>connects points<span> on a map that are of </span>equal<span> value. Examples of contour </span>lines<span> or isolines are isobars (pressure) and isotherms (</span>temperature<span>). Perhaps the prototypical example of a contour </span>line<span> is that which </span>connects points of equal<span> elevation (that is, height above sea level).</span>
