What type of cells provide support and strength to plants where growth has ceased?

Sclerenchyma cells are specialized plant cells that provide structural support and rigidity to areas of the plant where growth has ceased. These cells have thick, lignified cell walls, which make them exceptionally strong and durable. Sclerenchyma is typically found in mature tissues, and its primary function is to help maintain the integrity and shape of plant structures, such as stems and leaves.

In contrast, xylem is primarily involved in the transport of water and minerals from the roots to the rest of the plant, while phloem is responsible for transporting nutrients and sugars produced during photosynthesis. Collenchyma cells, on the other hand, provide support to young, growing parts of the plant and are characterized by unevenly thickened cell walls, allowing for flexibility. This distinction is crucial since sclerenchyma addresses the needs of mature, non-growing tissues, making it the correct choice for this question.