Plants share four characteristics that are structural and functional. Structurally, plants are separated into shoots and roots and they have protective layers that prevents water loss. Functionally, they synthesize their own food and use alternating reproductive processes in each generation.
The structural similarities of plants are the shoots, or the plant above ground, including the leaves, flowers and stems. The roots lie underground, anchor the plant and take in nutrients and water. Furthermore, cells jackets around the gametes retain moisture so they won't dry out and reproduction is more likely. Also, plant surfaces exposed to air have a waxy layer called the cuticle to prevent drying.
Functionally, most plants do not eat other organisms. They synthesize their food from light, water and carbon dioxide. In addition, plants alternate between haploid and diploid generations. Diploid generations have a set of chromosomes from both parent plants. Haploid is just one set of chromosomes.