What is alternation of generations in plants?

Explanation

**Step-by-Step Solution:**

1. **Definition of Alternation of Generations**: Alternation of generations, also known as Metagenesis or Heterogenesis, is a biological process in the life cycle of plants and certain algae where there is a regular alternation between two distinct forms: the haploid gametophyte and the diploid sporophyte.

2. **Haploid and Diploid Stages**: In this process, the multicellular haploid stage, called the gametophyte, has one set of chromosomes (n). This stage is responsible for producing gametes (sperm and eggs) through mitosis.

3. **Formation of Sporophyte**: The gametes produced by the gametophyte fuse during fertilization to form a diploid zygote, which then develops into a multicellular diploid sporophyte. The sporophyte has two sets of chromosomes (2n), which is the result of the combination of two gametes (n + n).

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