Provide an explanation of the life cycles in plants.

(N/A) $\rightarrow$ In plants,both haploid and diploid cells can divide by mitosis. This ability leads to the formation of different plant bodies - haploid and diploid.
$\rightarrow$ The haploid body produces gametes by mitosis. This plant body represents a gametophyte.
$\rightarrow$ Following fertilisation,the zygote also divides by mitosis to produce a diploid sporophytic plant body. Haploid spores are produced by this plant body by meiosis. These,in turn,divide by mitosis to form a haploid plant body once again.
$\rightarrow$ Thus,any plant possessing sexual reproduction forms the body. During the life cycle of any sexually reproducing plant,there is an alternation of generations between the gamete-producing haploid gametophyte and the spore-producing diploid sporophyte.
$\rightarrow$ However,different plant groups,as well as individuals representing them,differ in the following patterns:
$(1)$ Haplontic: Meiosis in the zygote results in the formation of haploid spores. The haploid spores divide mitotically and form the gametophyte. The dominant,photosynthetic phase in such plants is the free-living gametophyte. This kind of life cycle is termed as haplontic. Many algae such as $Volvox$,$Spirogyra$,and some species of $Chlamydomonas$ represent this pattern.
$(2)$ Diplontic: In all gymnosperms and angiosperms,the sporophyte is the dominant,photosynthetic,independent phase of the plant. The gametophytic phase is represented by the single to few-celled haploid gametophyte. This type of life cycle is termed as diplontic.