Theres the shoot system and the root system
the shoot system is above ground and includes the plants organs which are the leaves,stem,buds and flowers
The root system is below ground and includes roots as well as modified stem structures such as tubers and rhizomes
Mechanisms of evolution correspond to violations of different Hardy-Weinberg assumptions. They are: mutation, non-random mating, gene flow, finite population size (genetic drift), and natural selection.
Multiple species aka animals, humans, plants and all the species interactions :)