56, and that is only the magor volcanos inIndonesla
<span>The correct answer for the question that is being presented above is this one: "Topographic maps feature contour lines to portray the shape and elevation of the land. Topo maps render the three-dimensional ups and downs of the terrain on a two-dimensional surface. It also includes contours. Orthophoto maps</span> show land features using color-enhanced photographic images which have been processed to show detail in true position. They may or may not include contours."
High levels of dissolved oxygen
Ultramafic,as components of mafic rocks like olivine and pyroxene solidified at very high temperatures, so mafic minerals will decompose as the result of chemical weathering more rapidly than felsic minerals
True; with improvements in technology/manufacturing, acid rain became a major problem
