Which life cycle involves alternating haploid and diploid stages?

The life cycle that involves alternating haploid and diploid stages is known as alternation of generations. This process is a key feature in the life cycles of many plants, some algae, and fungi. In alternation of generations, an organism alternates between two distinct phases: the haploid gametophyte phase, where it produces gametes (sperm and eggs), and the diploid sporophyte phase, which arises from the fusion of gametes and produces spores.

During the haploid phase, the organism is capable of sexual reproduction, while in the diploid phase, it can reproduce asexually by creating spores that develop into new haploid organisms. This dual life cycle allows for genetic diversity through sexual reproduction as well as the ability to rapidly colonize environments using asexual reproduction.

In contrast, the other options do not describe this specific alternating life cycle. For instance, the fertilization cycle focuses on the specific event of gamete fusion rather than the entire life cycle; the reproductive cycle is a broader term that does not specifically refer to the alternation of phases; and the metamorphic cycle pertains to developmental changes in organisms such as amphibians and does not involve haploid and diploid stages.