Question 4
A hundred-year-old tree is still getting taller and thicker every year. What does this tell you?
The right answer is the one marked above.
It still has meristematic tissue, at its growing points. Apical meristems at every tip and lateral meristem all round the trunk go on dividing for as long as the plant lives.
Almost all of an old tree is permanent tissue — the trunk is mostly dead lignified xylem. Meristematic and permanent describe cells, not the age of the plant.