Most terrestrial plants (both bryophytes and tracheophytes) share some general structural and functional features. Plant bodies are divided into two regions, the underground root portion and the aerial shoot portion (including stem, leaves, flowers, and fruits). These different regions of the plant are dependent on each other, as each performs different essential functions. Land plants also share certain more specific adaptations that are essential to survival out of water. These include an impermeable waxy cuticle on the outer aerial surfaces, jacket cells around the reproductive organs, and stomata that allow gas exchange without risking excessive water loss.
Plants are also autotrophic, meaning that they produce their own food and do not use other organisms to supply organic nutrients the way animals do. Finally, the life cycle of plants follows a pattern called the alternation of generations, in which they fluctuate between haploid and diploid generations and sexual and asexual modes of reproduction.