Final answer:
The haploid-dominant life cycle, where the dominant phase is haploid, is characteristic of most fungi and some algae. In this cycle, the multicellular organism spends most of its time in the haploid state, only becoming diploid briefly to form a zygote that soon undergoes meiosis to revert to haploid spores.
Step-by-step explanation:
The type of reproduction in which the haploid phase of the life cycle is dominant is known as haploid-dominant life cycle. Most fungi and some species of algae exhibit this life cycle. In such organisms, the main body, or the ecologically significant phase, is haploid, which means that the cells contain a single set of chromosomes. During sexual reproduction, haploid cells from two parents fuse to form a diploid zygote. This zygote then immediately undergoes meiosis, creating four haploid spores with a new combination of genes, which can germinate and grow into a new multicellular haploid organism through mitosis.
On the other hand, a diploid-dominant life cycle, such as that of humans, features a multicellular diploid stage as the prominent phase, with the only haploid cells being the gametes. Plants exhibit an alternation of generations, which involves both haploid and diploid stages in a cycle.