At least 3.5 billion years
Lava<span>: Magma that reaches the earth's surface is called </span>lava<span>. It may be </span>acidic<span> or </span>basic<span>. </span>Acidic lava<span> is viscous, is lighter in color and has higher silica content. </span>Basic lava<span> is non-viscous, is darker in color and has lower silica content.</span>
Answer:
The terminus of a glacier advances if there is more accumulation than ablation, retreats if there is more ablation than accumulation, and remains stationary if accumulation is balanced with ablation.
Explanation:
In plate tectonics, a convergent boundary<span>, also known as a destructive plate </span>boundary<span> (because of subduction), is an actively deforming region where two (or more) tectonic plates or fragments of the lithosphere move toward one another and collide.</span>