Secondary meristem is located within and around the vascular tissues, and secondary meristems make the stem or root grow larger in diameter. Given these facts, what make the stem or root grow larger in diameter among the following options:
- heart cells
 - rainfall
 - bending light rays
 - vascular tissues
 - tissue boxes
 - plant cells
 - colors of the spectrum
 - Exfoliation


 

    vascular tissues     