Final answer:
Mesenchyme is an embryonic tissue that originates from the mesodermal layer and gives rise to all connective tissues. Mesenchymal cells, which are adult stem cells, facilitate tissue repair and regeneration throughout an individual's life.
Step-by-step explanation:
Mesenchyme is an embryonic connective tissue that derives from the mesodermal layer of the embryo. It is the precursor from which all connective tissues develop. Mesenchymal cells are the adult stem cells that have the potency to differentiate into various types of connective tissue cells, which are essential for repair and healing. These cells are widely distributed throughout the body and remain present in the adult to provide cells for replacement and the regeneration of injured connective tissues.
Therefore, phrases that correctly describe mesenchyme include that it develops from mesenchymal cells and that it's derived from the mesoderm. Additionally, mesenchyme is the source of cells that give rise to the body's connective tissues, including bone formation through processes like intramembranous and endochondral ossification, and the formation of joint structures.