volcanoes hope this helps
<span>Sinkholes, especially like the one that occurred in Mexico City, are often sign that the water reservoir is being depleted. Usually, the water underneath the ground helps stabilize it, however if there is suddenly open space or a cavern, it can collapse on its self causing a sink hole. This could also happen from fracking and drilling.</span>
<span>the most abundant type of rocks on earth are classified as - </span>a. igneous
