Final answer:
The vascular cambium is key to a tree's secondary growth, producing secondary xylem and phloem, which increases the tree's girth and contributes to the strength of the wood, while the cork cambium replaces the epidermis with bark.
Step-by-step explanation:
The vascular cambium plays a crucial role in secondary growth in trees by enabling the formation of new vascular tissues. This lateral meristem is responsible for the production of secondary xylem and phloem, leading to an increase in the diameter or girth of a stem or root over time. As the vascular cambium divides, it generates new cells: those oriented towards the inside of the stem mature into secondary xylem, which contributes to the wood and strength of the tree, while those oriented towards the outside differentiate into secondary phloem. The growth process includes the crushing of outer older cells, and the replacement of the epidermis with bark, which includes a cork layer produced by the cork cambium.
The correct answer to the question is C) By enabling the formation of new xylem and phloem.