Identify the CORRECT statements. P. Specialized parenchymatous cells with tannins and crystals of calcium oxalate are termed as sciereids. Q. The sieve elements of angiosperms are surrounded by companion cells and are essential component of phloem loading. R. The exudation of water by guttation occurs through trichomes. S. The bulliform cells control the unrolling and hygroscopic movement of grass leaves.

Statement Q is correct because sieve elements in angiosperms depend heavily on adjacent companion cells for metabolic support and phloem loading. Statement S is correct because bulliform cells are specialized epidermal cells that lose turgor and cause the unrolling or folding of grass leaves during water stress. Statements P and R are wrong because sclerids are dead mechanical cells, and guttation occurs via hydathodes, not trichomes.