Which of the five marked nodes in the tree above corresponds

Which of the five marked nodes in the tree above corresponds to the most recent common ancestor of a mushroom and a sponge? Justify your answer.

Solution

Out of the marked five nodes, the most recent common ancestor of both mushroom and sponge would be D.

There are only two common nodes, B and D out of which descendants are arising. B would be the first common ancestor for all the five - tomato, fern, sponge, mouse and mushroom. The second common ancestor which descends into sponge, mouse and mushroom is D , which shows two branches, one leading to mushrooms and the other leading to sponge and mouse. Thus the MOST RECENT COMMON ANCESTOR would be D.