According to their life expectancy, plants are divided into perennial, biennial and annual.
Trees, shrubs and many herbaceous plants are perennial. In the majority of perennial herbaceous plants, the aerial part dies off in autumn. In spring, the aboveground part of the plant develops again, since the roots of these plants and other underground organs with buds are preserved in the soil under the snow.
Perennial plants can reach a considerable age. Oak trees are found in the world, the age of which is about 2000 years.
Biennial plants live for almost two years. In the first year, they usually only develop roots, stem and leaves. In the second year, these plants develop new shoots, they bloom and bear fruit with seeds, and dry up in the fall. Biennial plants are, for example, cabbage, beets, radishes, carrots.
In the first year, carrots develop root and leaves. In the temperate climate zone, carrots are harvested and eaten in autumn.
Annual plants develop from seed in spring, bloom, form fruit with seeds, and then die off. Annual plants are, for example, asters, oats, tomatoes, cucumbers.
An interesting experiment can be done with annuals such as cucumbers. Plant cucumber seeds and photograph the sprouts every day. Photos can be used to make a video showing the development of a cucumber.