On the basis of what trait are plants classified as annual, biennial and perennial? give examples

Plants are characterized by “lethality” based on the temporal characteristics of their flowering and the life span of the plant organism. Annuals vegetate during one season, bloom in the same season and die off. These include most of the meadow flowers, cereals (including cultivated ones). Biennials in the growing season accumulate a nutritious supply of sugars in the roots or underground shoots, and the next season they throw out shoots with flowers (carrots, pansies, daisies). Perennials live long and often bloom. These include trees and shrubs, but including many herbs (artichoke, tarragon, valerian).