What do all plant life cycles have in common

Diploid and haploid phases alternate.

Explanation:

The life cycle of all plants has alternating diploid and haploid phases. In haploid phases (n) plants have only half the number of chromosomes in the diploid phase (2n). During the haploid phases the plant form is called gametophyte and in the sporophyte diploids, so we have the gametoophytic generations in the haploid phase and the sporophytic generations in the diploid phase.

answer; i do believe that the correct answer is; ///mendelian genes are at specific loci on the chromosome and, in turn, segregate during meiosis;