Which of the following is a characteristic of sclerenchyma cells?

Sclerenchyma cells are recognized for their thick, even, and rigid cell walls, which are typically composed of lignin—a complex organic polymer. This structural characteristic provides strength and support to the plant tissues in which they are found. Sclerenchyma cells are often dead at maturity, which differentiates them from other cell types that remain alive and have flexible walls, such as parenchyma.

The rigidity of sclerenchyma cells allows them to provide structural support for various parts of the plant, contributing to the overall stability of stems and other plant organs. Their significant strength is especially important in seed coats and the fibers used in textiles, illustrating their critical role in plant anatomy and function.

In contrast, other types of cells mentioned in the choices have distinct features: thin and flexible cell walls are more indicative of parenchyma cells; living cells that conduct photosynthesis refer more to chlorenchyma, a specialized type of parenchyma containing chloroplasts; and vascular cells, such as xylem and phloem, serve different functions in transporting water, nutrients, and sugars throughout the plant.