To maintain turgor pressure, cells in both the leaves and stems of most non-woody or herbaceous plants contain a) chloroplasts. b) starch granules. c) many mitochondria. d) a large central vacuole.

The correct answer is (d) A large central vacuole.

Plant cell has very large central vacuole that helps in maintaining the turgor pressure of the cell and it also helps in maintaining the stability of plant cell. The maximum amount of water is absorbed in the vacuole and helps to keep the cell erect. In mature plants the vacuole tend to very large and provides mechanical support to the cell. It also helps in waste disposal, protection, growth and storage of plant materials.