Which of the Following is an Example of Alternation of Generations

Question

Which of the following is an example of alternation of generations?
A) A grandparent and grandchild each have dark hair, but the parent has blond hair.
B) A diploid plant (sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain (gametophyte).
C) A diploid animal produces gametes by meiosis, and the gametes undergo fertilization to produce a diploid zygote.
D) A haploid mushroom produces gametes by mitosis, and the gametes undergo fertilization, which is immediately followed by meiosis.
E) A diploid cell divides by mitosis to produce two diploid daughter cells, which then fuse to produce a tetraploid cell.

Accepted Answer

Alternation of generations involves a life cycle in which there are two distinct multicellular stages - a haploid stage (gametophyte) and a diploid stage (sporophyte) - that alternate with each other. In option B, the diploid sporophyte produces haploid spores by meiosis, which develop into a multicellular haploid pollen grain (gametophyte) that produces haploid gametes. The fertilization of the gametes produces a diploid zygote, which grows into a new diploid sporophyte, completing the alternation of generations cycle.