The following diagram shows the branching tree for four kingdoms and some of their shared derived characteristics. A slanting line is shown. There are four lines drawn vertically on this line at equal intervals. There is a black circle between each pair of these vertical lines. Protists, Plants, Fungi, Animals are written on top of each vertical line in order from left to right. Common Cell is written on the left most end of the sloping line. The second black circle has X written on it. The fourth black circle has Are Mobile written on it. What characteristic can be written at point X? Explain your answer in complete sentences.