The correct answer that would best complete the given statement above is the term PARALLAX. The apparent movement of a star when seen a different position is called parallax. This is the <span>displacement or difference in </span>the apparent position<span> of an object viewed along two </span>different <span>lines of sight. Hope this answers your question.</span>
As the magma from the volcano rises up it begins to settle as crystals and causes the chemical compositions to change and the magma has less of magnesium and more of the silica contents.
A volcano that has more of silica oxide and a high temperature but low silica contents results in a more fluid or basaltic magma and a high content result in a viscous magma and they are of high explosive in nature like the Stromboli volcano and Mount Vesuvius.