A life cycle is a series of changes in form that an organism undergoes, returning to the starting state. There are 3 types of cycles:Haplontic life cycle — the haploid stage is multicellular and the diploid stage is a single cell, meiosis is "zygotic".
Diplontic life cycle — the diploid stage is multicellular and haploid gametes are formed, meiosis is "gametic".
Haplodiplontic life cycle (also referred to as diplohaplontic, diplobiontic, or dibiontic life cycle) — multicellular diploid and haploid stages occur, meiosis is "sporic".