Which of the following statements about secondary growth is true? Select all that apply. Select all that apply. The lateral meristems add to the thickness of roots and shoots, but the cambium layers do not increase in circumference. The vascular cambium and cork cambium start actively dividing only after primary growth in that area of a root or shoot has stopped. The oldest secondary vascular cells (xylem or phloem) are the farthest from the vascular cambium layer. Due to the single direction of growth produced by the cork cambium, the oldest cork cells are closest to the cork cambium.