What describes a life cycle that includes both a multicellular diploid form and a multicellular haploid form?

The concept of a life cycle that includes both a multicellular diploid form and a multicellular haploid form is known as alteration of generations. This is commonly observed in many plants, fungi, and some algae, where the organism alternates between two distinct phases: the gametophyte, which is haploid, and the sporophyte, which is diploid.

In the haploid phase, the gametophyte produces gametes (sperm and eggs) through mitosis. When these gametes fuse during fertilization, they form a diploid zygote, which then develops into the multicellular diploid sporophyte. This sporophyte produces haploid spores through meiosis, completing the cycle.

This specific life cycle contrasts with metamorphosis, which involves changes in body structure during an individual's life and does not pertain to haploid or diploid multicellular phases, or with sexual and asexual reproduction, which are more about the methods of producing offspring rather than the phases involved in the life cycle.